“Although I respect Bill and Tom, we still don’t have information from the Obama administration on what went so tragically wrong in Benghazi,” she said in a statement. “This requires a public appearance by the secretary of state herself.”

Mrs. Clinton has said that she takes responsibility for the failure to successfully defend the Benghazi compound in the Sept. 11 attack. But she has never been questioned by lawmakers about how decisions were made by the Obama administration to establish the compound and protect it.

When a House oversight committee held a hearing on the Benghazi attack in October, the State Department was represented by a senior management official and a midlevel official from the department’s Bureau of Diplomatic Security. The former chief security officer for the embassy in Libya, Eric A. Nordstrom, told that panel that some of his requests for additional security were ignored. But the State Department’s under secretary for management, Patrick Kennedy, countered that none of the steps proposed by Mr. Nordstrom would have altered the outcome in Benghazi because the embassy was based in Tripoli.

The political debate over the Benghazi attack has already claimed one victim: the ambassador to the United Nations, Susan E. Rice. Ms. Rice had been the Obama administration’s top choice to succeed Mrs. Clinton as secretary of state, but last week she withdrew her name from consideration for the job because of the controversy over her initial description of the attack as a spontaneous demonstration that spun out of control.

Acting on the advice of her doctors, Mrs. Clinton will not go to the State Department this week but will work from home, the State Department said.

“Secretary Clinton developed a stomach virus, leading to extreme dehydration, and subsequently fainted,” her doctors, Dr. Lisa Bardack of the Mount Kisco Medical Group and Dr. Gigi El-Bayoumi of George Washington University, said on Saturday. Because of her illness, Mrs. Clinton on Tuesday canceled a planned trip to Morocco, where she was expected to formally recognize a new Syrian opposition coalition as the legitimate representative of the Syrian people. President Obama conveyed the recognition instead in an interview with ABC News.