WASHINGTON -- Secretary of State Hillary Clinton, who skipped an overseas trip this past week because of a stomach virus, sustained a concussion after fainting, the State Department said Saturday.

The 65-year-old Clinton, who's expected to leave her job soon, was recovering at home after the incident last week and is being monitored by doctors, according to a statement by aide Philippe Reines.

No further details were available.

President Obama telephoned his top diplomat Saturday to wish her well, a White House official said.

The State Department said Clinton was dehydrated because of the virus, fainted and sustained a concussion. She will work from home this week and looks forward to returning to the office at Foggy Bottom "soon," the statement said.

The Senate Foreign Relations Committee said it won't hear from Clinton as planned at a hearing Thursday into the Sept. 11 attack against a U.S. diplomatic outpost in Benghazi, Libya, that killed four Americans, including the U.S. ambassador, Christopher Stevens.

The House Foreign Affairs Committee also said Clinton no longer would give scheduled testimony at its hearing Thursday on Libya.

Senior State Department officials William Burns and Thomas Nides are to take Clinton's place at both hearings.

Clinton's aides on Saturday informed the Senate committee chairman, Sen. John Kerry, about her health, and the Massachusetts Democrat "insisted that, given her condition, she could not and should not appear" as planned, said Kerry spokeswoman Jodi Seth. Obama is expected to nominate Kerry to succeed Clinton.

Clinton backed out of a trip to North Africa and the Persian Gulf on Monday because she was sick. She caught the virus during a recent visit to Europe.

The former first lady is known for her grueling travel schedule and is the most traveled secretary of state, having visited 112 countries while on the job.