Organizations were singled out because they included the words "tea party" or "patriot" in their applications for tax-exempt status, said Lois Lerner, who heads the IRS division that oversees tax-exempt groups.

In some cases, groups were asked for their list of donors, which violates IRS policy in most cases, she said.

"That was wrong. That was absolutely incorrect, it was insensitive and it was inappropriate. That's not how we go about selecting cases for further review," Lerner said at a conference sponsored by the American Bar Association.

"The IRS would like to apologize for that," she added.

Lerner said the practice was initiated by low-level workers in Cincinnati and was not motivated by political bias. After her talk, she told The AP that no high level IRS officials knew about the practice.

Agency officials found out about the practice last year and moved to correct it, the IRS said in a statement. The statement did not specify when officials found out.

About 75 groups were inappropriately targeted. None had their tax-exempt status revoked, Lerner said.

Senate Republican Leader Mitch McConnell of Kentucky called on the White House to investigate.

"Today's acknowledgement by the Obama administration that the IRS did in fact target conservative groups in the heat of last year's national election is not enough," McConnell said. "I call on the White House to conduct a transparent, government-wide review aimed at assuring the American people that these thuggish practices are not under way at the IRS or elsewhere in the administration against anyone, regardless of their political views."

Many conservative groups complained during the election that they were being harassed by the IRS. They accused the agency of frustrating their attempts to become tax exempt by sending them lengthy, intrusive questionnaires.

The forms, which the groups made available at the time, sought information about group members' political activities, including details of their postings on social networking websites and about family members.

Certain tax-exempt charitable groups can conduct political activities but it cannot be their primary activity.

IRS Commissioner Douglas Shulman told Congress in March 2012 that the IRS was not targeting groups based on their political views.

"There's absolutely no targeting. This is the kind of back and forth that happens to people" who apply for tax-exempt status, Shulman told a House Ways and Means subcommittee.

Shulman was appointed by President George W. Bush. His 6-year term ended in November. President Barack Obama has yet to nominate a successor. The agency is now being run by acting Commissioner Steven Miller.

"The Ways and Means Committee has persistently pushed the IRS to explain why it appeared to be unfairly targeting some political groups over others a charge they repeatedly denied," said Rep. Charles Boustany, R-La., chairman of the Ways and Means oversight subcommittee.

"The IRS's 'too little too late' response is unacceptable, and I will continue to work to ensure there are protections in place so no American, regardless of political affiliation, has their right to free speech threatened by the IRS," Boustany said.

Tea Party groups were livid on Friday.

"I don't think there's any question we were unfairly targeted," said Tom Zawistowski, who until recently was president of the Ohio Liberty Coalition, an alliance of tea party groups in the state.

Zawistowski's group was among many conservative organizations that battled the IRS over what they saw as its discriminatory treatment of their effort to gain non-profit status. The group first applied for non-profit status in June 2009, and it was finally granted on Dec. 7, 2012, he said one month after Election Day.

During the 2012 election, many tea party groups applied for tax-exempt status under section 501 (c) (4) of the federal tax code, which grants tax-exempt status to social welfare groups. Unlike other charitable groups, these organizations are allowed to participate in political activities but their primary activity must be social welfare.

That determination is up to the IRS.

Lerner said the number of groups filing for this tax-exempt status more than doubled from 2010 to 2012, to more than 3,400. To handle the influx, the IRS centralized its review of these applications in an office in Cincinnati.

Lerner said this was done to develop expertise among staffers and consistency in their reviews. As part of the review, staffers look for signs that groups are participating in political activity. If so, IRS agents take a closer look to make sure that politics isn't the group's primary activity, Lerner said.

As part of this process, agents in Cincinnati came up with a list of things to look for in an application. As part of the list, they included the words, "tea party" and "patriot," Lerner said.

"It's the line people that did it without talking to managers," Lerner. "They're IRS workers, they're revenue agents."

In all, about 300 groups were singled out for additional review, Lerner said. Of those, about a quarter were singled out because they had "tea party" or "patriot" somewhere in their applications.

The IRS statement said that once applications were chosen for review, they all "received the same, even-handed treatment."

Lerner said 150 of the cases have been closed and no group had its tax-exempt status revoked, though some withdrew their applications.

"Mistakes were made initially, but they were in no way due to any political or partisan rationale," the IRS said in a statement. "We fixed the situation last year and have made significant progress in moving the centralized cases through our system."

Marcus S. Owens, who spent a decade leading the IRS division that oversees tax-exempt organizations, said Friday that it made sense that the problem arose among workers in Cincinnati because the agency "really has delegated a lot of authority" to local offices to make decisions about handling their workload.

But Tea Party groups weren't buying the idea that the decision to target them was solely the responsibility of low-level IRS workers.

"It is suspicious that the activity of these 'low-level workers' was unknown to IRS leadership at the time it occurred," said Jenny Beth Martin, national coordinator for Tea Party Patriots, which describes itself as the nation's largest tea party organization. "President Obama must also apologize for his administration ignoring repeated complaints by these broad grassroots organizations of harassment by the IRS in 2012, and make concrete and transparent steps today to ensure this never happens again."

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Associated Press reporters Alan Fram and Steve Peoples in Boston contributed to this report.

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Follow Stephen Ohlemacher on Twitter: http://twitter.com/stephenatap

BOGOTA (Reuters) - Colombian President Juan Manuel Santos on Monday refused to be drawn into a war of words between his predecessor - and harshest critic - and Venezuela's new president, Nicholas Maduro.

Maduro, elected last month to replace the late Hugo Chavez, said on Friday he had evidence that Alvaro Uribe, president of Colombia from 2002 until mid 2010, was conspiring with the Venezuelan opposition to kill him.

Santos was reprimanded on social media and by another former president for not responding to Maduro's explosive comments, which also included an allegation that Uribe could have been involved in the death of a Venezuelan journalist.

Santos said he would not comment publicly on the dispute - a veiled poke at Uribe, who has used his Twitter account to defend himself against Maduro's attacks that he is a "Mafioso" and "murderer."

"The dignity of former presidents is defended better - not with shouts or public insults - but through the corresponding diplomatic channels," Santos said on his Twitter account.

While Santos is playing it safe, Maduro's outburst against the former head of state threatens to disrupt the diplomatic peace between the two nations, formed by Chavez and Santos after years of cross-border bickering.

Caracas broke off diplomatic relations with Uribe's government in 2010 after he accused the leftist Chavez of harboring FARC rebel leaders inside Venezuela.

Santos, who has frequently sparred in public with Uribe, was chided by former President Andres Pastrana for not responding to Maduro's comments.

"What's at stake is Colombia's dignity," said Pastrana, who held office before Uribe. "We can't let a former president be insulted because there are discrepancies between Santos and Uribe."

For many Colombians, it was not surprising that Santos did not jump to defend Uribe, his former boss when he served as defense minister, since the two have been at loggerheads for the best part of his presidency.

A conservative and staunch U.S. ally, Uribe has been Santos' fiercest and most public critic, most rabidly against his ties with Caracas and his bid to reach a peace accord with the Revolutionary Armed Forces of Colombia.

Maduro, the self-professed "son of Chavez," has made a series of accusations since taking office last month.

He has accused the United States of seeking to kill opposition leader Henrique Capriles to stir chaos and spark a coup. He later said he himself was the target of an assassination plot by mercenaries from El Salvador.

Uribe on Sunday urged Colombia's attorney general to investigate Maduro over the "irresponsible slanders and threats," in case the Venezuelan leader ever visits Colombia.

(Editing by Doina Chiacu)

WASHINGTON (Reuters) - The proliferation of hacking tools known as zero-day exploits is raising concerns at the highest levels in Washington, even as U.S. agencies and defense contractors have become the biggest buyers of such products.

White House cybersecurity policy coordinator Michael Daniel said the trend was "very worrisome to us."

Asked if U.S. government buying in the offensive market was adding to the problem, Daniel said more study was needed. "There is a lot more work to be done in that space to look at the economic questions...so we can do a better job on the cost-benefit analysis," he said.

Some security experts say the government's purchasing power could help instead of hurt. They argue the U.S. government should bring the market into the open by announcing it will pay top dollar for zero-days and then disclosing all vulnerabilities to the companies concerned and their customers.

"Given that people are now buying vulnerabilities, the U.S. should simply announce that it is cornering the market, that they will pay 10 times anyone else," said Dan Geer, chief information security officer at In-Q-Tel, the U.S. intelligence community's venture capital firm. He said he was speaking outside of his official capacity.

Richard Clarke, who served as counter-terrorism chief in the White House before becoming a cybersecurity advisor there a decade ago, said the government should at least review the exploits it has and disclose the vast majority.

"In some rare cases, perhaps the government could briefly withhold that information in order to run a high-priority collection mission," he said. "Even then, however, the government should closely monitor to see if anyone else has discovered the vulnerability and begun to use it."

Howard Schmidt, who served as White House cybersecurity czar under Obama, said he agreed with Clarke's approach. Asked if he had made the same argument during his recent two and a half years in the White House, he said he couldn't betray confidences by going into detail.

But Schmidt added: "The entire discussion on cascading effects and the sort of unintended consequences of any type of malware was had more than once...That's the discussion that needs to continue to take place."

(Reporting by Joseph Menn; Editing by Jonathan Weber and Claudia Parsons)

SANTA CLARA, Calif. (AP) -- The genetic testing instrument business Affymetrix Inc. expects first-quarter revenue below Wall Street expectations.

The Santa Clara, Calif., company said Tuesday it expects total revenue of about $78 million for the quarter that ended March 31. That includes about $19 million from its eBioscience segment. Affymetrix will report full results April 30 after markets close.

Analysts expect, on average, revenue of $83.3 million, according to FactSet.

The company also said Tuesday it expects to report cash on hand of at least $38 million as of March 31.

Affymetrix technology helps analyze biological systems at the cell, protein and gene levels. For instance, it provides kits for molecular biology applications like DNA sequencing and protein analysis.

Its shares finished at $4.66 on Monday. They have traded in a 52-week range of $2.96 to $5.50.

Members of one of the classical music world's most celebrated orchestras will perform Sunday behind bars. Looking on will be celebrated conductor, Riccardo Muti (MOO' tee).

The concert in Chicago's Juvenile Temporary Detention Center is a culmination of a weeklong musical workshop for inmates organized in part by the Chicago Symphony Orchestra.

Muti has made community outreach a priority since taking the helm of the CSO in 2010. The goal is to inspire at-risk youth and impart greater appreciation for music.

The detention center holds mainly teenage boys awaiting trial on charges ranging from dope dealing to murder.

The works being performed include compositions inmates helped compose. Italian-born Muti will be in attendance but wasn't expected to conduct.

A brief statement read on national television by Communications Minister Ernesto Villegas late Monday carried the sobering news about the charismatic 58-year-old socialist leader's deteriorating health.

Villegas said Chavez is suffering from "a new, severe infection." The state news agency identified it as respiratory.

Chavez has been undergoing "chemotherapy of strong impact," Villegas added without providing further details.

Chavez has neither been seen nor heard from, except for photos released in mid-February, since submitting to a fourth round of surgery in Cuba on Dec. 11 for an unspecified cancer in the pelvic area. It was first diagnosed in June 2011.

The government says he returned home on Feb. 18 and has been confined to Caracas' military hospital since.

Villegas said Chavez was "standing by Christ and life, conscious of the difficulties he faces."

He also took the opportunity to lash out at "the corrupt Venezuelan right" for what he called a psychological war seeking "scenarios of violence as a pretext for foreign intervention."

The communications minister called on Chavez's supporters, who include thousands of well-armed militiamen, to be "on a war footing."

Upon Chavez's death, the opposition would contest the government's candidate in a snap election that it argues should have been called after Chavez was unable to be sworn in on Jan. 10 as the constitution stipulates.

Indeed, the campaigning has already begun, although undeclared. Vice President Nicolas Maduro, who Chavez has said should succeed him, has frequently commandeered all broadcast channels, Chavez-style, to tout the "revolution" and vilify the opposition.

Chavez has run Venezuela for more than 14 years as a virtual one-man show, gradually placing all state institutions under his personal control. But the former army paratroop commander who rose to fame by launching a failed 1992 coup, never groomed a successor with his force of personality.

Chavez was last re-elected on Oct. 7, and his challenger, youthful Miranda state Gov. Henrique Capriles, is expected to again be the opposition's candidate.

One of Chavez's three daughters, Maria Gabriela, expressed thanks to well-wishers via her Twitter account. "We will prevail!" she wrote, echoing a favorite phrase of her father. "With God always."

Maduro said last week that the president had begun receiving chemotherapy around the end of January.

Doctors have said that such therapy was not necessarily to try to beat Chavez's cancer into remission, but could have been palliative, to extend Chavez's life and ease his suffering.

Dr. Carlos Castro, scientific director of the Colombian League Against Cancer in Bogota, Colombia, said "it's difficult to predict" when Chavez might die, but he believes "it's a matter of days."

Castro said that Chavez could face further respiratory complications if he receives more intense chemotherapy treatment.

If the president's medical team "gives him strong chemotherapy again, then it would not be surprising if some infections reappear," Castro said in a telephone interview.

While in Cuba, Chavez suffered a severe respiratory infection in late December that nearly killed him, Maduro said last week. A tracheal tube was inserted then and government officials have said his breathing remained labored.

Libardo Rodriguez, a 60-year-old man who sells orange juice on the street in Caracas, said he was very worried after Monday evening's announcement regarding Chavez's condition. The government, he added, should provide more information.

"We are worried because he does not appear. The truth is that I don't know what's happening," said Rodriguez, a Chavez supporter.

Rodriguez complained about what he described as the government's vague updates regarding Chavez's health.

"There are many rumors and nobody knows who to believe," he said. "We hope he's alive."

In Cuba, Chavez has undergone a series of radiation treatments and chemotherapy after his operations. But the entire treatment regimen was kept far from public scrutiny.

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Associated Press writer Vivian Sequera in Bogota, Colombia, contributed to this report.

Coach, Lockheed Martin, DuPont and Travelers all rose after they reported results that were better than analysts expected.

Markets swooned briefly, then quickly recovered, shortly after 1 p.m. when The Associated Press' Twitter account was hacked and a fake tweet was posted about an attack at the White House.

Major indexes rose about 1 percent.

The Dow Jones industrial average increased 152 points to 14,719.

The Standard & Poor's 500 index rose 16 points to 1,578 and the Nasdaq composite rose 35 points to 3,269.

The gains were broad. Four stocks rose for every one that fell on the New York Stock Exchange. Volume was average at 3.5 billion shares.

'Menace to the Public Health' Declares Oklahoma Board of Dentistry

Officials at thehave filed a 17-count complaint against Harrington, a dentist with offices in Tulsa and Owasso, Okla. who has been practicing dentistry for 36 years, after finding rusty instruments, drug vials with expiration dates from 1993, reused needles, an autoclave for sterilizing instruments that hadn't been tested in six years when monthly tests are required and learning that unlicensed dental staff have been allowed to start IVs according to the.

Harrington is scheduled to appear for an April 19 hearing that could result in permanent revocation of his license.

Investigation of Harrington's Practice Triggered by Blood Test Results

The investigation into Harrington's dental practice by the, the, and Oklahoma Board of Dentistry and now consultation with thewas triggered by the discovery of a person with no known risk factors for HIV or hepatitis C who tested positive for both viruses and had had a dental procedure performed at the likely time of exposure. That dental procedure was done at one of Harrington's dental offices.

'This Is Not an Outbreak'

, epidemiologist at the Oklahoma State Department of Health, explains that the investigation into the positive blood test results in what the agency is referring to as an "index person" is in its early stages and there is no indications of an outbreak of HIV or hepatitis C. At this point, the health agencies cannot be certain the index person contracted the viruses at Harrington's practice, but they cannot overrule the possibility, particularly in light of the conditions found at his offices.

Seven Thousand Patients and Counting

Notification letters are being mailed today by the Tulsa Health Department to the the 7,000 known patients of Harrington; records dated back to 2007 provided these patient names, but there are likely other people who have been patients of Harrington's in his nearly four decades of practice. The Tulsa Health Department has afor previous patients of Harrington to contact with any questions or concerns and to learn what blood-testing recommendations are appropriate for them.

Free Testing Offered by Tulsa Health Department

Both the Oklahoma State Department of Health and the Tulsa Health Department havebeing offered to patients of Harrington, beginningand continuing all next week. Free testing will be done for HIV, hepatitis B and hepatitis C with the results being confidential. Those people who have received notification letters should bring them at the time of testing and people who were patients of Harrington previous to 2007 should contact the patient information hotline to receive more information.

Bottom Line

If the charges against Harrington are substantiated, it is a sad commentary on one who promises first to do no harm. His office is currently closed, so no one else can become a potential victim of unethical practices.

Those people who have been patients of Harrington's, no matter when that occurred, should avail themselves of the free blood testing being offered. It may be frightening to consider the outcome of the tests, but it is more frightening and life-endangering not to know.

NEW YORK (AP) -- A sharp decline in the price of oil this month is making gasoline cheaper at a time of year when it typically gets more expensive. It's a relief to motorists and business owners and a positive development for the economy.

Over the past three weeks, the price of oil has fallen by 9 percent to $89 a barrel. That has helped extend a slide in gasoline prices that began in late February. Nationwide, average retail prices have fallen by 27 cents per gallon, or 7 percent, since Feb. 27, to $3.52 per gallon. Analysts say pump prices could fall another 20 cents over the next two months.

The price of oil is being driven lower by rising global supplies and lower-than-expected demand in the world's two largest economies, the United States and China. As oil and gasoline become more affordable, the economy benefits because goods become less expensive to transport and motorists have more money to spend on other things. Over the course of a year, a decline of 10 cents per gallon translates to $13 billion in savings at the pump.

Diesel and jet fuel have also gotten cheaper in recent weeks, which is good news for truckers, airlines and other energy-intensive businesses.

"It makes a big difference to my bottom line," says Mike Mitternight, owner of a heating and air conditioning service company in Metairie, La. He has five pickup trucks that can burn $1,000 of gas per week when prices are near $4 a gallon. Lately he's been paying as little as $3.19, and saving $200 a week.

Gasoline prices typically rise in the late winter and spring as refiners shut down parts of their plants to perform maintenance and begin making more costly blends of gasoline required by federal clean-air regulations. The trend was earlier and less dramatic this year. Pump prices only came within 15 cents of last year's peak.

Oil production is growing quickly in the U.S. and Canada, helping boost global supplies. And some of the factors that pushed prices higher the two previous years political turmoil in North Africa and the Middle East and refinery disruptions in the U.S. haven't materialized this spring.

At the same time, demand for fuels is growing slower than expected. China, the world's biggest oil importer, is experiencing slower-than-expected economic growth. And much of Europe is in recession.

In the U.S., wintry weather in the Midwest and Northeast has kept more drivers off the roads this spring, analysts say.

The typical U.S. household will spend an estimated $326 on gasoline this April, the equivalent of 7.8 percent of median household income, according to Fred Rozell, an analyst at GasBuddy.com. That's $38 less than last April, when households spent 8.8 percent of their income on gas.

"It's the difference between going out to dinner one more time or not," says Diane Swonk, chief economist at Mesirow Financial. "It matters."

The U.S. government releases its initial estimate of economic output during the first three months of 2013 on Friday. Economists forecast the economy grew at an annual rate of 3.1 percent, compared with 0.4 percent in the final three months of 2012.

Philip Verleger, an economist who studies energy prices, says that many monthly household expenses are fixed, but gasoline is one of the few big expenses that varies. That means when gasoline prices rise or fall people notice.

"This is the equivalent of a pay raise," he says.

Shippers and airlines are also benefiting. Fuel is by far airlines' biggest and most volatile cost. A one-cent decline in the price of jet fuel saves the U.S. airline industry $180 million over a year, according to the industry group Airlines for America. Lower energy prices also give potential customers more money to spend on air travel.

Airlines aren't ready to celebrate yet because the relief could prove to be short-lived, says John Heimlich, chief economist at Airlines for America. "It looks promising but we're not counting our chickens," he said.

Political turmoil or refinery problems could crop up at any time. Analysts are particularly worried about the transition of power in Venezuela, a major oil exporter, after the death of President Hugo Chavez. Violence has erupted in the wake of a closely contested election, and the financial situation of the country is precarious. Analysts worry that the country's oil production could slip.

Also, refinery maintenance in the Midwest is already affecting prices there. Drivers in Ohio, Michigan and Indiana are paying only slightly less than they did last year at this time, and prices there have been creeping up over the last couple of weeks.

Gasoline prices reached a high this year of $3.79 per gallon on Feb. 27. Last year's peak was $3.94, and it came on April 6; last year's low was $3.22 on Dec. 20. The average price for all of 2012 was $3.63 per gallon. The Energy Department forecasts the 2013 average will be $3.56.

Analysts say there are limits to how far oil and gasoline prices will fall. Countries in the developing world are still growing fast and pushing world oil demand higher, perhaps to a record this year. And if oil prices fall too far drillers will be forced to cut production to try to stem the decline.

That means Mike Mitternight, the small business owner in Louisiana, won't likely get his wish: He'd like to see gasoline prices between $2 and $3 per gallon.

"I still think it's high and we could bring it lower," he says.

Jonathan Fahey can be reached at http://twitter.com/JonathanFahey.