WASHINGTON » U.N. Ambassador Susan Rice told lawmakers today that her initial explanation of the deadly Sept. 11 raid in Libya was wrong, but her concession failed to mollify three Republican senators who signaled they would oppose her possible nomination to be secretary of state.

In a closed-door meeting that Rice requested, the ambassador answered questions from Sens. John McCain, Lindsey Graham and Kelly Ayotte about her much-maligned explanations about the cause of the attack on the U.S. diplomatic mission in Benghazi, Libya, that killed Ambassador Chris Stevens and three other Americans. She was joined by acting CIA Director Michael Morell.

"The talking points provided by the intelligence community, and the initial assessment upon which they were based, were incorrect in a key respect: There was no protest or demonstration in Benghazi," Rice said in a statement after the meeting. "While we certainly wish that we had had perfect information just days after the terrorist attack, as is often the case the intelligence assessment has evolved."

Rice’s unusual visit to Capitol Hill — typically only nominees meet privately with lawmakers — reflects the Obama administration’s campaign for the current front-runner to replace Secretary of State Hillary Rodham Clinton against some strenuous GOP opposition.

"We are significantly troubled by many of the answers that we got and some that we didn’t get concerning evidence that was leading up to the attack on the consulate," McCain told reporters after emerging from the hour-plus session that he described as candid.

Said Graham: "Bottom line I’m more disturbed now than I was before that 16 September explanation." He said in a later interview that Rice went "far beyond the flawed talking points" and should be held accountable.

"I’m more troubled today," said Ayotte, who argued that it was clear in the days after the attack that it was terrorism and not a spontaneous demonstration prompted by an anti-Muslim video.

The White House remained defiant in its support for Rice, arguing that she was relying on an assessment from the intelligence community and had no responsibility in compiling the information on the cause of the attack. It dismissed what it characterized as a fixation on her national television appearances five days after the raid.

"The focus on, some might say, obsession on comments made on Sunday shows seems to me and to many, to be misplaced," spokesman Jay Carney told reporters at a White House briefing.

House Democrats, including female members of the Congressional Black Caucus, have suggested that the GOP opposition to Rice is sexist and racist. Senate Democrats, who will increase their advantage to 55-45 in the next Congress, said Rice could win confirmation if Republicans recognize the unfairness of penalizing her for the intelligence community’s talking points.

"It is so unfair to hold her responsible for something that she didn’t produce and which the intelligence community has specifically stood by," said Sen. Carl Levin, D-Mich., chairman of the Armed Services Committee.

Despite lingering questions over her public comments after the Benghazi attack, Rice has emerged as the top candidate on a short list of possible successors to Clinton, with Senate Foreign Relations Committee Chairman John Kerry, D-Mass., seen as her closest alternative.

The strong statements from the three senators clouded Rice’s prospects only two days after Republican opposition seem to be softening. Rice planned meetings on Wednesday with Sen. Bob Corker of Tennessee, who is in line to become the top Republican on the Foreign Relations Committee, and Sen. Susan Collins, R-Maine.

Corker said today that he had concerns with a possible nomination.

"When I hear Susan talk she seems to me like she’d be a great chairman of the Democratic National Committee," Corker said. "There is nobody who is more staff supportive of what the administration does. That concerns me in a secretary of state."

A senior Senate aide said the administration was sounding out moderate members of the Foreign Relations Committee, such as Corker and Sen. Johnny Isakson, R-Ga. Assessing the prospects for Rice before Obama makes any announcement would avoid the embarrassment of a protracted fight with the Senate early in the president’s second term and the possible failure of the nominee.

On talk shows the weekend following the attack, which took place on the 11th anniversary of 9/11, Rice was given talking points that described the attack as a spontaneous protest of the film, even though the Obama administration had known for days that it was a militant assault.

Republicans called her nomination doomed, leading to a vigorous defense of her by Obama in his first postelection news conference. Since then, GOP lawmakers have appeared to soften their views. McCain, who said earlier this month that would he do everything in his power to scuttle a Rice nomination, had said Sunday that he was willing to hear Rice out before making a decision.

Rice, who at 48 is relatively young, has been known to covet the job for years, but was passed over for Clinton in 2009.

Several diplomats currently serving with Rice said that what she lacked in Clinton’s star power, she could make up with a blunter approach that demands attention and has marked her tenure thus far at the United Nations.

Associated Press writers Matthew Lee in Washington and Edith M. Lederer in New York contributed to this report.