Secretary of State Hillary Rodham Clinton will testify before Congress about an official investigation into an attack in September that killed four Americans in Benghazi, Libya, the House Foreign Affairs Committee announced Thursday.

Rep. Ileana Ros-Lehtinen (R-Fla.), who chairs the committee, said at a hearing on the Benghazi attack that Clinton “has committed to testifying before our committee and the Senate Foreign Relations Committee” on a report by the Accountability Review Board, a five-member panel formed to investigate the attack and make recommendations. Ros-Lehtinen did not specify when Clinton would testify but noted that the board is expected to finish its report by “early to mid-December.”

The Sept. 11 assault by armed militants on a U.S. diplomatic post in Benghazi and a nearby annex used by CIA personnel claimed the lives of J. Christopher Stevens, the U.S. ambassador to Libya, and three other Americans: Information Management Officer Sean Smith and security personnel Glen Doherty and Tyrone Woods. Stevens was visiting from his post in the Libyan capital, Tripoli, at the time. Doherty and Woods were former Navy SEALs.

The Benghazi attack has become the subject of intense controversy because of conflicting accounts of how it originated and charges that the U.S. government should have heeded warnings to strengthen security at its posts in the eastern Libyan city.

Prominent Republican senators called Wednesday for the establishment of a temporary select committee to investigate the attack and condemned Susan E. Rice, the U.S. ambassador to the United Nations, for initial statements about it that they said were inaccurate and misleading.

Documents: Security incidents in Libya since June 2011

The comments by Sens. John McCain (Ariz.) and Lindsey O. Graham (S.C.) drew a sharp rebuke from President Obama, who told a news conference Wednesday that “they should go after me” instead of trying to “besmirch” Rice’s reputation.

“We are committed to identifying what went wrong and what needs to be done to prevent any further American lives from being lost in such attacks,” Ros-Lehtinen said at her committee’s hearing on the Benghazi attack Thursday morning.

“The coordinated preplanned and brazen attacks against the U.S. Consulate in Benghazi on September 11 was an outrage,” she said in an opening statement. “Also disgraceful is the sad parade of conflicting accounts of the attack that we have received from administration officials in the weeks and months since.”

She charged that the Obama administration ignored warnings of “the deteriorating security situation in Benghazi” and “denied repeated requests for additional security measures” at the U.S. outposts.

The open hearing came as senior CIA, FBI and State Department officials briefed the House and Senate intelligence committees about the Benghazi attack behind closed doors.

Democratic lawmakers who attended said the briefings essentially vindicated Rice by confirming that the account she gave on Sunday television talk shows five days after the attack was based on the best intelligence assessments available at the time. Rice had said that the assault “was not a preplanned, premeditated attack” but a “spontaneous reaction” to protests in Cairo over an anti-Muslim video that outraged the Arab world.

“In the end, the assessment was still the same — that in Benghazi, you had a group of extremists who took advantage of a situation, and unfortunately we lost four American lives,” Rep. C.A. Dutch Ruppersberger (Md.), the top Democrat on the House intelligence committee, said after the hearing.

He noted that when CIA Director David H. Petraeus first briefed lawmakers the day after the Benghazi attack, he called it spontaneous but added that extremists were also involved, Reuters news agency reported.

“It was a combination of both. What General Petraeus basically said in the beginning was that this was spontaneous — but that there were extremists, there were terrorists, involved in this situation,” the agency quoted Ruppersberger as saying.

Petraeus, who resigned Nov. 9 because of a sex scandal, is scheduled to testify Friday about the Benghazi attack.

Another Democrat on the House intelligence committee, Rep. Adam Schiff (Calif.), told reporters that he did not believe the intelligence community had politicized the information in provided on the attack.

“They gave us the best initial assessments, and those proved inaccurate, but they warned us those assessments were subject to change as they got more information,” he said, according to the Associated Press.

The House Foreign Affairs Committee hearing Thursday featured a testy exchange between Republican and Democratic members over the matter.

Rep. Dana Rohrabacher (R-Calif.) charged that “the president himself has intentionally misinformed — read that, lied — to the American people in the aftermath of this tragedy.” Now, he said, Obama “has the gall to float the name” of Rice as a possible nominee to replace Clinton as secretary of state. He described Rice as “the actual vehicle used to misinform the American people during this crisis.”

Rohrabacher told the committee: “The arrogance and dishonesty reflected in all of this is a little bit breathtaking, and it’s about time that the president of the United States decided to to level with the American people.... Let’s not stonewall this issue and cover up mistakes, as appears to be happening today.”

That brought a strong retort from Rep. Gary L. Ackerman (D-N.Y.), who accused Republicans of hypocrisy in cutting administration requests for security funding and then making political hay out of the inevitable results.

The administration “requested for worldwide security $440 million more than you guys wanted to provide,” Ackerman angrily told committee Republicans. “A quarter of a billion dollars in security upgrades that you refused to make in this committee, and then you have the audacity to come here and say why wasn’t the protection of these people provided for. And the answer is because you damn didn’t provide it.”

Ackerman continued: “You reduced what the administration asked for to protect these people. And the answer to the question, how do you protect these people, [is] it costs money, believe it or not.”