Secretary of State Hillary Clinton fainted and suffered a concussion, the department said Saturday. She is now recovering at home.
“While suffering from a stomach virus, Secretary Clinton became dehydrated and fainted, sustaining a concussion,” deputy assistant secretary Philippe Reines said in a statement.
Clinton, who has said she will not serve as secretary of State in President Obama’s second term, cancelled a trip to the Middle East last week after becoming ill.
She was due to testify before Congress on Dec. 20 about the investigation into the deaths of four Americans at the U.S. Consulate in Benghazi on Sept. 11.
Clinton will not testify as scheduled before the Senate Foreign Relations Committee, said Jodi Seth, a spokeswoman for Chairman John Kerry (D-Mass.).
The State Department told Kerry of Clinton's concussion on Saturday morning, and, when he heard, Kerry insisted that she not attend the hearing.
"Senator Kerry was relieved to hear that the secretary is on the mend, but he insisted that given her condition, she could not and should not appear on Thursday as previously planned, and that the nation’s best interests are served by the report and hearings proceeding as scheduled with senior officials appearing in her place," Seth said.
Clinton deputies Tom Nides and Bill Burns will testify in her place, Seth said.
Kerry is considered the leading candidate to replace Clinton as secretary of State after U.N. Ambassador Susan Rice withdrew her name from consideration last week.
Speculation increased late Saturday that Obama had decided to nominate Kerry as the next secretary of State.
An unidentified source told CNN that a formal announcement could come as early as next week.
ABC News, quoting unidentified sources, said news, including the mass shooting at a school in Newtown, Connecticut, had delayed the announcement.
Nides and Burns will also testify in Clinton's place that day before the House Foreign Affairs Committee. The panel's chairman, Rep. Ileana Ros-Lehtinen (R-Fla.), said, however, that Clinton's testimony will be required in the future.
“I am sorry to learn of Secretary Clinton’s ill health and I wish her a quick and full recovery," Ros-Lehtinen said in a statement. “Although I respect Bill and Tom, we still don’t have information from the Obama administration on what went so tragically wrong in Benghazi that resulted in the deaths of four patriotic Americans.
"We have been combing through classified and unclassified documents and have tough questions about State Department threat assessments and decision-making on Benghazi. This requires a public appearance by the secretary of state herself. Other cabinet secretaries involved should also be held publicly accountable."
“The American people and the families of the four murdered public servants and other brave Americans injured deserve no less,” she added.
Ros Lehtinen will hand over the committee gavel to Rep. Ed Royce (R-Calif.) in January.
Clinton told Barbara Walters in an interview that aired this week she's "healthy" and has "incredible stamina and energy."
Clinton also fainted while giving a speech in 2005 in Buffalo, N.Y., after complaining of a stomach virus.
--This report was originally published at 12:30 p.m. and last updated at 8:35 p.m.