WASHINGTON (AP) - The Internal Revenue Service apologized Friday for what it acknowledged was "inappropriate" targeting of conservative political groups during the 2012 election to see if they were violating their tax-exempt status.
IRS agents singled out dozens of organizations for additional reviews because they included the words "tea party" or "patriot" in their exemption applications, said Lois Lerner, who heads the IRS division that oversees tax-exempt groups. In some cases, groups were asked for lists of donors, which violates IRS policy in most cases, she said.
The agency - led at the time by a Bush administration appointee - blamed low-level employees, saying no high-level officials were aware. But that wasn't good enough for Republicans in Congress, who are conducting several investigations and asked for more.
"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 underway at the IRS or elsewhere in the administration against anyone, regardless of their political views," said Senate Republican leader Mitch McConnell of Kentucky.
White House spokesman Jay Carney declared it was indeed inappropriate for the IRS to target tea party groups. But he brushed aside questions about whether the White House itself would investigate.
Instead, Carney said the administration expects a thorough investigation by the Treasury Department's inspector general for tax administration. That office has been looking into the issue since last summer. The IRS inspector general also is investigating, with a report expected soon.
Carney said he did not know when the White House first learned that tea party groups were being targeted.
Lerner acknowledged it was wrong for the agency to target groups based on political affiliation.
"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. 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.
The IRS is an independent agency within the Treasury Department that enforces the nation's tax laws. Revelations that the agency was targeting political groups because they were affiliated with a movement that is critical of President Barack Obama could become a new headache for the White House.
"The admission by the Obama administration that the Internal Revenue Service targeted political opponents echoes some of the most shameful abuses of government power in 20th century American history," said House Speaker John Boehner, R-Ohio.
Many conservative groups complained during the campaign 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 have made available, sought information about group members' political activities, including details of their postings on social networking websites and about family members.
IRS Commissioner Douglas Shulman told Congress in March 2012 that the IRS was not targeting groups based on politics.
"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.
The IRS said senior leaders were not aware that specific groups were being targeted at the time of the hearing.
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.
Rep. Charles Boustany, R-La., chairman of the Ways and Means oversight subcommittee, requested a trove of documents from the IRS on Friday, including all communications containing the words "tea party" and "patriot."
House Majority Leader Eric Cantor, R-Va., and the House Oversight and Government Reform Committee have also promised investigations.
There has been a surge of politically active groups claiming tax-exempt status in recent elections - conservative and liberal. Among the highest profile are Republican Karl Rove's group, Crossroads GPS, and the liberal Moveon.org.
These groups claim tax-exempt status under section 501 (c) (4) of the federal tax code, which is for 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.
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."
"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 discriminatory treatment. The group first applied for nonprofit status in June 2009, and it was finally granted on Dec. 7, 2012, he said - one month after Election Day.
"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 grass-roots organizations of harassment by the IRS in 2012, and make concrete and transparent steps today to ensure this never happens again."
Associated Press writers Alan Fram in Washington and Steve Peoples in Boston contributed to this report.