[attach id=254706 size="medium"]Outgoing acting IRS Commissioner Steven Miller at a House Ways and Means Committee hearing on the Internal Revenue Service targeting conservative groups on Capitol Hill in Washington, on Friday. Photo: Reuters[/attach]

The outgoing head of the US Internal Revenue Service has angered Republican lawmakers by resisting their demands that he identify who at the tax-collection agency had inappropriately targeted conservative groups for extra scrutiny.

But during the first hearing into a growing IRS scandal that could preoccupy Washington for months, Republicans did learn that a top official in President Barack Obama’s administration knew that the IRS was looking into targeting by the tax agency nearly a year ago.

That detail could encourage Republicans’ efforts to link the scandal to the White House as the administration faces a series of setbacks that threaten to derail Obama’s second-term priorities, which include revamping immigration laws and reaching a budget deal with Republicans.

Friday’s hearing was dominated by lawmakers’ grilling of acting IRS Commissioner Steven Miller, who provided few clear answers while apologising for the extensive questioning and years-long delays that many conservative groups have experienced after applying for tax-exempt status.

I think what happened here is that foolish mistakes were made by people trying to be more efficient

Miller, who was fired by Obama last Wednesday, said the overly aggressive scrutiny of such groups was the result of mismanagement, not partisan politics. His comments echoed the findings of a Treasury Department inspector general’s report released last week.

“I think what happened here is that foolish mistakes were made by people trying to be more efficient,” said Miller, who will leave his post this week and be replaced by Daniel Werfel, a budget specialist in the administration.

Miller said he did not know who had come up with the idea to single out groups that appeared to be politically conservative for intense reviews of whether they qualified to be tax-exempt.

He said that although the added scrutiny was wrong, he did not think that IRS employees had broken any laws.

That claim drew the ire of Republicans on the House of Representatives Ways and Means Committee, as did Miller’s shrugs when lawmakers pressed him over why he had not told Congress about the probe even though he learned about it a year ago.

“This is offensive, to hear this testimony,” said Representative Tom Reed, a Republican from New York.

The hearing did seem to yield some fruit for Republicans who are trying to cast the targeting of conservative ‘Tea Party’ and ‘Patriot’ groups as a political initiative encouraged by the Obama administration, a claim the White House rejects.

Critics have hammered the White House on the IRS scandal, its handling of the deadly attack on the US mission in Benghazi, Libya, and the Justice Department’s seizure of phone records of Associated Press journalists in a criminal probe into intelligence leaks.

The Treasury Department’s internal watchdog, J. Russell George, told the House panel that Deputy Treasury Secretary Neal Wolin, an Obama political appointee, learned nearly a year ago that a government watchdog was looking into inappropriate targeting by the IRS.

Wolin, the No. 2 official at Treasury, is due to testify this week before the House Oversight and Government Reform Committee.

In a statement, the Treasury Department said it made the probe public last fall in an annual report that listed more than 200 other internal investigations.

Treasury Secretary Jack Lew was told about the investigation when he took office in March, the department said, but neither he nor Wolin was told about its findings even as a preliminary version circu-lated elsewhere within the department.