From the BBC:

Veteran US Senator Ted Kennedy is said to be well again after collapsing from "fatigue" at President Barack Obama's inauguration lunch in Washington.

"After testing, we believe the incident was brought on by simple fatigue," Dr Edward Aulisi of Washington Hospital Center said in a statement.

"Sen Kennedy is awake, talking with family and friends, and feeling well."

Mr Obama voiced concern for the senator, who was diagnosed last year with a cancerous brain tumour.

Senator Robert Byrd was also reported to have been taken ill, but his office later said he was fine, Reuters said.