President Obama on Wednesday forced out the acting director of the Internal Revenue Service and pledged to work with Congress as it investigates why the tax agency was inappropriately targeting conservative groups that opposed Obama and other Democrats.

IRS Acting Director Steven Miller was asked to resign less than a week after the public learned that the agency was giving closer scrutiny to conservative groups seeking tax-exempt status and delaying approval of their status change.

"Americans are right to be angry about it -- and I'm angry about it," Obama said during a hastily scheduled briefing in the East Room of the White House. "I'll do everything in my power to make sure nothing like this ever happens again."

Miller's firing and the administration's decision earlier Wednesday to release scores of emails about the terrorist attacks in Benghazi, Libya, marked the start of a what promises to be an extensive damage-control campaign by the White House to quell criticisms over a trio of controversies, including the IRS probing of conservative groups, the Justice Department's spying on journalists and claims that the president misled the nation about the nature of the Sept. 11 Benghazi attacks that left an ambassador and three others dead.

Obama said other changes will be made at the IRS to prevent similar abuses in the future, but said nothing about additional firings.

"I will not tolerate this kind of behavior in any agency, but especially in the IRS, given the power that it has, and the reach that it has in all of our lives," he said.

House Oversight and Government Reform Committee Chairman Darrell Issa, R-Calif., who is leading one of the congressional probes into the tax agency's actions, told CNN that he was pleased Obama would work with lawmakers to institute changes at the IRS.

"The president struck the right tone," he said.

Facing growing pressure from Republicans, the White House on Wednesday released more than 100 pages of emails about Benghazi.

In releasing the documents, Obama's surrogates were looking to push the narrative that the Central Intelligence Agency -- not the White House -- made the most substantial edits to talking points initially describing the terrorist strike as a spontaneous demonstration by protesters upset about an anti-Muslim video created in the U.S.

The emails show both the White House and intelligence community were involved in crafting the talking points but that the White House did not remove the references to terrorism. Republicans have laid heavy blame for the changes on the State Department.

"The seemingly political nature of the State Department's concerns raises questions about the motivations behind these changes and who at the State Department was seeking them," said Brendan Buck, a spokesman for House Speaker John Boehner, R-Ohio. "This release is long overdue and there are relevant documents the administration has still refused to produce. We hope, however, that this limited release of documents is a sign of more cooperation to come."