It is taken as inevitable in military circles that initial reports of combat operations are almost always imperfect. Sometimes major details are wrong in the first telling, due either to misunderstandings or errors. As a result, the armed forces generally take the time necessary to double-check crucial pieces of the story before making it public.

In the bin Laden case, the Pentagon was not the lead provider of information for an operation led by the CIA and followed in real time by the national security team and by Obama, who gave the order to proceed late last week. The bin Laden killing stood head and shoulders above most other military operations in the demand for fast details.

The US account of what happened inside bin Laden's Abbottabad compound is so far the only one most Americans have. Pakistan has custody of the people rounded up afterward, including more than two dozen children and women. Differing accounts purporting to be from witnesses have appeared in Pakistani and Arab media, and on the Internet.

Pakistan's army urged the government Thursday to cut in the number of US military personnel inside the country in protest of the American raid, and threatened to cut cooperation with Washington if it should stage more unilateral actions on its territory.

In the Pentagon's first on-the-record comment about the raid, defense policy chief Michele Flournoy said Thursday that the US has no "definitive evidence" that Pakistan knew that the targeted compound was bin Laden's hideout. Regardless, the Pakistanis must now show convincingly their commitment to defeating al-Qaida, Flournoy said. Anything short of that, she said, will risk losing congressional support for continued US financial aid to Islamabad.

Republican Rep. Ted Poe, who supports withholding aid to Pakistan until it demonstrates such a commitment, was among those who found it hard to believe that authorities there were unaware of bin Laden's presence in a military town with a military academy.

"Bin Laden's hideaway was just a stone's throw from Pakistan's West Point," he said. "That's like John Dillinger living right down the street from the FBI and the FBI not knowing about it." Dillinger was a notorious bank robber and gangster in the 1930s who eventually was killed in an FBI ambush.

Once elements of the official version of Sunday's operation in Pakistan began changing, and in an effort to slow the demand for more details, White House press secretary Jay Carney referred reporters to the Pentagon for more information, even though the Pentagon had already said it would say no more. The Pentagon canceled its daily public press briefings each day this week.

"The nature of the mission, the nature of what happened Sunday, combined with the effort to get that information quickly, resulted in the need to clarify some facts," Carney said aboard Air Force One Thursday en route to New York. He said the administration should be given credit for correcting mistakes when it found them.