The House Ways and Means Committee held the first congressional hearing into the Internal Revenue Service's improper targeting of Tea Party and other conservative groups, including some Hispanic..

The just-ousted acting chief of the IRS, Steven Miller, expressed regret for the heightened reviews.

"I want to apologize on behalf of the Internal Revenue Service for the mistakes that we made and the poor service we provided," Miller told the committee. "The affected organizations and the American public deserve better. Partisanship and even the perception of partisanship has no place at the Internal Revenue Service," he added.

Rep. Dave Camp, R-Mich, chairman if the committee, said the IRS' improper use of tougher scrutiny of conservative groups seeking tax-exempt status seems part of a broader pattern of intimidation and cover-ups by the Obama administration.

He referred to a "culture of cover-ups and intimidation in this administration," but offered no other examples.

"The affected organizations and the American public deserve better. Partisanship and even the perception of partisanship has no place at the Internal Revenue Service."

- Steven Miller

The IRS scandal involving the apparently unjustified targeting of Tea Party and other conservative groups also hit the Hispanic community.

George Rodriguez, former president of the San Antonio Tea Party, said that when the organization applied for non-profit status, leaders were intimidated by IRS workers with excessive paperwork and meddling questions.

“They asked us all sorts of things that were out of the norm,” Rodriguez, now head of the conservative South Texas Alliance, told Fox News Latino. “We knew these questions were not the norm and we had our suspicions about them.”

Rodriguez said the group received a questionnaire from the IRS with “well over 50 questions,” including inquiries into who the group met with, where they held their meetings, who was in attendance and what the subject of their internal emails were.

The Obama administration has been forced on the defensive about last September's terrorist attack in Benghazi, Libya, that killed the U.S. ambassador and three other Americans, and the government's seizure of The Associated Press' telephone records as part of a leaks investigation.

Republicans are hoping to link the issues in an effort to raise questions about President Barack Obama's credibility and make it harder for him to press a second-term agenda.

Camp's remark drew a sharp retort from the committee's top Democrat, Rep. Sander Levin of Michigan. Levin said if the hearing became a preview of the 2014 political campaigns, "we'll be making a very, very serious mistake."

Even so, Levin also was harshly critical of the IRS's treatment of conservative groups. He said Lois Lerner, who heads the IRS division that makes decisions about tax-exempt groups, should be "relieved of her duties."

Though Miller and another top IRS official are stepping down, Camp said that would not be enough.

"The reality is this is not a personnel problem. This is a problem of the IRS being too large, too powerful, too intrusive and too abusive of honest, hardworking taxpayers," Camp said.

Miller said the IRS struggled to efficiently handle growing numbers of applications for tax-exempt status, and that political bias was not the reason for the increased scrutiny.

Lawmakers had asked the IRS repeatedly about complaints from conservative groups that their applications were being treated unfairly, but said Miller and others never told them the groups were being targeted.

Members of Congress said this continued even after May 2012, when the agency says Miller was briefed on the practice. Miller was previously a deputy commissioner whose portfolio included the unit that made decisions about tax-exempt status.

Republicans have spent the past few days trying to link the IRS' improper scrutiny of conservatives to Obama. The president has said he didn't know about the targeting until last Friday, when Lerner acknowledged at a legal conference that conservative groups had been singled out.

"I promise you this, that the minute I found out about it, then my main focus was making sure that we get the thing fixed," Obama said Thursday.

Many of the groups were applying for tax-exempt status as social welfare organizations, which are allowed to participate in campaign activity if that is not their primary activity. The IRS judges whether that imprecise standard is met.

Attorney General Eric Holder has said the FBI was investigating whether the IRS may have violated applicants' civil rights.

Obama has rejected the idea of naming a special prosecutor to investigate the episode, saying the investigations by Congress and the Justice Department were sufficient.

Obama has named Daniel Werfel, a top White House budget officer, to replace Miller.

Based on reporting by the Associated Press.

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