Ailing U.S. Senator Edward Kennedy collapsed at an inaugural lunch for Democratic President Barack Obama on Tuesday and was evacuated by medical staff, apparently suffering from convulsions, a congressional aide said.

Kennedy was wheeled out of the Capitol building on a stretcher surrounded by police and taken away in an ambulance, according to a Reuters witness.

Obama, who just hours before had been sworn in as the new U.S. president, said his prayers were with Kennedy and his family. Kennedy, 76, is battling a life-threatening brain tumor.

Kennedy, one of the Senate's most respected Democrats, is the brother of the late President John F. Kennedy.

He had a seizure last May and was found to have a malignant brain tumor, which required surgery. He missed much of the rest of the year in Congress, but returned to the Senate this year, determined to help Obama pass sweeping legislation to expand health care.

Television networks reported that Kennedy's convulsions started after fellow Sen. Robert Byrd, 91, a West Virginia Democrat, also suffered a medical issue and was taken out of the room. His office later said he was fine.