Allied warplanes bombed a civilian-occupied bunker in Baghdad because they believed it was sheltering key Iraqi military officers - not a command-and-control center as U.S. officials have claimed, a London newspaper reported Friday.

The Independent, a respected daily, said its story was based on the comments of a senior U.S. military official in Riyadh, Saudi Arabia, who insisted on anonymity.It contradicts the official U.S. position on Wednesday's bombing, which Iraqi authorities say killed as many as 500 people.

Independent reporter Robert Fisk quoted the unidentified U.S. official as saying, "There's not a soul who believes that it was a command-and-control bunker."

"I think the official statement on this will change in the coming days," the official said. "The military did believe it contained soldiers. We thought it was a military personnel bunker."

In Washington, the Pentagon's night duty officer denied The Independent's report.

"We bombed it because it was a command-and-control center," Lt. Col. Steve Roy said Thursday night.