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 the al Qaeda leader was not armed.

"I know for a fact that shots were exchanged during this operation," said a Pentagon official.

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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.

But 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."

Citing US officials, NBC reported that four of the five people shot to death in the operation that killed bin Laden, including the al Qaeda leader, were unarmed and never fired a shot -an account that differs from the administration's original assertions the Navy SEALS engaged in a prolonged firefight.

House Armed Services Committee Chairman Buck McKeon said the identification of bin Laden included a DNA comparison with bin Laden's mother and three sons.

"He was identified multiple ways. DNA photograph analysis, there is no question," Smith added.

The House Armed Services Committee was not shown pictures of bin Laden but some members asked to see them so they could tell constituents they saw them, McKeon said.

Another member of the panel, Representative Rob Andrews, said the more people that could validate bin Laden's death, the less likely the conspiracy theorists could thrive. Andrews said he would like to see the photos to help "stamp out conspiracy nonsense."