Top US defense officials said there was no evidence Pakistan's leadership was aware Osama bin Laden was in their country before a US military raid killed him, and they cautioned against punitive action against Islamabad over the incident.

Defense Secretary Robert Gates told a Pentagon news conference he had seen "no evidence at all" that senior Pakistani leaders knew the Al Qaeda chief's whereabouts before the raid and said "in fact, I've seen some evidence to the contrary."    

Bin Laden was killed earlier this month in a compound in Abbottabad, a garrison town near the Pakistani capital. The incident deeply embarrassed Pakistan's military and spy agencies and led to calls by members of the US Congress for a tougher approach toward the country.   

But Gates and Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, both said the raid had cost Pakistan dearly and cautioned against any action that could harm relations or interrupt the flow of US aid.   

"If I were in Pakistani shoes, I would say I've already paid a price. I've been humiliated. I've been shown that the Americans can come in here and do this with impunity," Gates said. "And I think we have to ... recognise that they see a cost in that and a price that has been paid."    

"I don't think we should underestimate the humbling experience that this is," Mullen said, stressing the "internal soul-searching" underway in the Pakistani military. "Their image has been tarnished ... and they care a lot about that. They're a very proud military."    

Gates said Pakistani officials indicated a willingness to go after Al Qaeda and Afghan insurgent leaders themselves and had warned the United States against trying another raid on their territory similar to the bin Laden assault.

"I think this provides us an opportunity, and I think we ought to take them up on that," Gates said, adding that it would give Pakistan a chance to address the "frustration and the skepticism" over the relationship being expressed in the US Congress.   

"It is their desire now to do this themselves. And I think they certainly understand the importance of it," Mullen said. But he added that "we all need to make sure that they understand very clearly that this priority isn't going to go away and that these safe havens ... for these leaders have to be eliminated."    

Mullen said General Ashfaq Pervez Kayani, Pakistan's chief of army staff, had committed in the past to going after leaders of the Haqqani network, one of the insurgent groups fighting in Afghanistan.
   
He said the raid had created difficulties for Pakistan's military, and while Kayani had indicated a desire to keep the relationship going "I think we both recognise it's going through a very difficult time right now."    

"I think we need to give them some time and space to work on some of the internal challenges that came out of this," he said. - Reuters