President Obama said the conduct involving the Internal Revenue Service's targeting of conservative groups for extra tax scrutiny was "inexcusable" and that acting IRS Commissioner Steven Miller is out.

"Americans have a right to be angry about it and I am angry about it," the president said. "I will not tolerate this kind of behavior in any agency but especially the IRS given the power that it has and the reach that it has in all of our lives."

"[I]t should not matter what political stripe you're from ... the fact of the matter is that the IRS has to operate with absolute integrity," he said.

Obama said Treasury Secretary Jack Lew had asked for and accepted Miller's resignation in hopes of restoring confidence in the agency going forward. No successor has yet been named.

"It is with regret that I will be departing from the IRS as my acting assignment ends in early June," Miller said in a memo to IRS employees. "[T]here is a strong and immediate need to restore public trust in the nation's tax agency. I believe the Service will benefit from having a new Acting Commissioner in place during this challenging period. As I wrap up my time at the IRS, I will be focused on an orderly transition."



Obama said the administration will hold other responsible parties accountable and will work with Congress to put in place safeguards to prevent this from happening in the future.

"I will do everything in my power to make sure nothing like this happens again," he said at the White House.

Earlier, the speaker of the House of Representatives raised the possibility of jail time for law violations in the growing scandal.



"My question isn't about who is going to have to resign, my question is who is going to jail over this scandal," John Boehner told reporters.

The House Oversight and Government Reform Committee will hold a hearing on May 22, according to an aide for Rep. Darrell Issa, chairman of the Republican committee.



Deputy Treasury Secretary Neil Wolin; former IRS Commissioner Doug Shulman; Lois Lerner, chief of the IRS tax exempt unit; and Treasury Inspector General for Tax Administration J. Russell George are being asked to testify.

The Justice Department began a criminal investigation Tuesday, while a number of congressional Republicans called for the resignation of acting IRS Commissioner Steven Miller.

(Read More: Obama: IRS Focus on Conservative Groups 'Outrageous')

On Friday, a separate House committee will hold the first hearing on the matter since it erupted last week. George and Miller will testify there.

"There are laws in place to prevent this type of abuse," Boehner said, referring to the IRS's giving extra scrutiny to requests for tax-exempt status by Tea Party and other conservative groups.

"Someone made a conscious decision to harass and hold up these requests," he said. "We need to know who they are, whether they violated the law. Clearly, someone violated the law."