WASHINGTON - US officials reaffirmed on Wednesday that there was a firefight at the compound in Pakistan where Osama bin Laden was killed, despite growing questions about the Obama administration's version of events and revelations that the al Qaeda leader was not armed."I know for a fact that shots were exchanged during this operation," said a Pentagon official.After a briefing by senior intelligence and defense officials, members of the House Armed Services Committee declined to discuss details of what they had been told.However, asked about bin Laden being shot unarmed, the senior Democrat on the panel, Representative Adam Smith, told reporters the US assault team did come under fire."They came in at night. It was dark. There were people moving around. They were fired at by, I think more than one person," Smith said. "There were weapons in the area. It was a fast moving situation in which they felt threatened and they responded accordingly."