Several, including Sens. Kelly Ayotte of New Hampshire as well as Graham and McCain, said later that they remained concerned and would try to block her nomination.

Graham said in a statement Thursday that he respects Rice’s decision but that he continues to question what happened in Libya on Sept. 11.

“When it comes to Benghazi I am determined to find out what happened – before, during, and after the attack,” he said. “Unfortunately, the White House and other agencies are stonewalling when it comes to providing the relevant information. I find this unacceptable.”

A spokesman for McCain said the senator thanks Rice for her service to her country and wishes her well.

“He will continue to seek all the facts about what happened before, during and after the attack on our consulate in Benghazi that killed four brave Americans,” spokesman Brian Rogers said.

U.S. Ambassador Chris Stevens and information management officer Sean Smith were killed when the consulate came under attack. Several hours later, two other Americans, Glen Doherty and Tyrone Woods, died at a CIA compound a mile away where surviving Americans from the consulate fled.

Republicans criticized Rice for describing the attack on Sunday talk shows as stemming from a spontaneous protest against an anti-Islam video and not as a terrorist operation, suggesting that it was a deliberate bid to protect Obama’s record on terrorism in the closing weeks of his re-election campaign. Rice said she relied on talking points the intelligence community provided, an initial assessment that turned out to be incorrect.

Rice, a 48-year-old Stanford University graduate and Rhodes scholar, earned a reputation as a confident, hard-charging diplomat dating to Bill Clinton’s presidency. Her sometimes blunt style has earned her as many friends as critics.

Another complication was Rice’s wealth and the suggestion of a possible conflict of interest. She and her Canadian-born husband own millions of dollars worth of stock in Canadian energy and pipeline companies that would profit from the construction of the proposed Keystone XL pipeline.

Rice violated no laws and properly revealed the stock on government financial disclosure forms, according to government watchdog groups. But if she had become secretary of state, one of her first acts may have involved the pipeline’s permit.

Hannah Allam of the Washington Bureau contributed to this report.