Washington (CNN) -- The ability of the United States to enter Pakistan, kill Osama bin Laden and leave without detection was a humiliation to Pakistanis, Secretary of Defense Robert Gates said Wednesday.
But Gates and the chairman of the Joint Chiefs of Staff, Adm. Mike Mullen, insisted there is no evidence Pakistani's senior leadership knew of the bin Laden compound in Abbottabad, Pakistan.
"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 told reporters at the Pentagon, responding to a question about what should be done if someone in Pakistan's government did know. "I think we have to recognize that they see a cost in that and a price that has been paid."
Mullen told reporters the incident was a "humbling experience" for the Pakistanis that has led to "internal soul-searching."
"They've been through a lot tied to this, and their image has been tarnished. And they care, as we all do, and they care a lot about that. They're a very proud military," Mullen said.
Both he and Gates said there is nothing to suggest senior Pakistani leadership knew the al Qaeda leader was in their midst. The United States does suspect some in the government, military or intelligence knew, but for now that is just a U.S. suspicion. They said they have found no evidence to support it.
"I mean, the supposition is somebody," Gates said. "We don't know whether it was, you know, retired people, whether it was low-level. Pure supposition on our part. It's hard to go to them with an accusation when we have no proof that anybody knew."
Mullen said the relationship between the two countries faces challenges going forward but its continuance is crucial for the United States.
"I think it would be a really significantly negative outcome if the relationship got broken," Mullen said.
Gates said he is frustrated by the Pakistani reluctance to go after al Qaeda and Taliban elements in northwest Pakistan. The raid on bin Laden's compound has opened an opportunity to address that issue again but the Pakistanis have warned the United States that another such covert raid would not be tolerated.
"The Pakistanis, over the last couple of weeks, have expressed the view that they are willing to go after some of these people and that we should not repeat the bin Laden operation, because they will undertake this themselves," Gates said.
The secretary and the chairman also expressed great concern about all the details on the raid that have been made public.
Gates noted an agreement had been reached in the government not to discuss "operational details" but "that lasted about 15 hours."
"We want to retain the capability to carry out these kinds of operations in the future. And when so much detail is available, it makes that both more difficult and riskier," he told reporters.
Mullen warned the impact of all the leaks to the media is "close to jeopardizing this precious capability that we have."
His criticism was not aimed only at those inside the government who are talking to the press without authorization. In addition, he said, "we've had far too many retired members who've spoken up."