Gen. Petraeus briefly collapses during hearing

General David Petraeus, chief of the U.S. military's Central Command, delivers a speech at the Royal United Services Institute for Defence and Security Studies (RUSI) Land Warfare Conference in central London in this June 9, 2010 file photo.

WASHINGTON (Reuters) - Gen. David Petraeus, who is in charge of U.S. forces in Iraq and Afghanistan, briefly collapsed at a Capitol Hill hearing on Tuesday, most likely from dehydration, and then regained his composure.

Petraeus, a fitness fanatic who was treated for prostate cancer last year, said he became "light headed" during the Senate Armed Services Committee hearing and was a little dehydrated.

"It wasn't Senator McCain's questions," he joked later, referring Arizona Senator John McCain who was questioning him at the time over the pace of military action in Afghanistan.

Petraeus, 57, appeared to slump over his seat before being helped by aides and walking out of the room. He told reporters after recovering: "(I) got dehydrated, I think." He said ate a couple of bananas and felt better.

The hearing was adjourned and will resume on Wednesday.

"He's eating. He probably didn't have enough water to drink coming in here this morning. But he appears to be doing very much better," Senator Carl Levin, chairman of the Armed Services Committee, told the hearing.

(Reporting by Sue Pleming, Susan Cornwell and Adam Entous; Editing by David Storey)