Gates said the performance of both Pakistan's military and civilian government over the past 16 months had exceeded Washington's expectations, in an interview with Al-Jazeera, the Qatar-based satellite news channel.
Gates said that he was pleased with the security of Pakistan's nuclear arsenal, calling the arrangements in place "sufficient and adequate."
"I'm quite comfortable that the security arrangements for the Pakistani nuclear capabilities are sufficient and adequate," he said.
He said that assessment was "based both on our own understanding of the security arrangements that the Pakistanis have for their weapons and their capabilities, their laboratories and so on. But also the insurances we have been given by the Pakistanis."
Gates cited Pakistan's "success" in the Swat Valley, where two million people fled a punishing military offensive against Taliban insurgents beginning in late April.
"I think if you look back, 15 or 16 months, the Pakistani government has performed admirably," Gates said, according to a transcript.
"I believe that the Pakistani government, both the civilian side and the military side, have performed better than almost anyone's expectations in the region, or in this country, or elsewhere, and we are very impressed by that and we are prepared to be helpful, to help the Pakistanis in any way we can."
The military says it has now cleared that area of insurgents, and about 1.3 million displaced people have returned. But skirmishes continue, raising fears that the Taliban are regrouping in the mountains.
"I think people would not have predicted the success of the Pakistani army," Gates said.
"I think people would not have predicted the success in the Pakistani government's effective dealing with internally displaced persons as a result of a military operation and how many of them have returned to Swat and how effective the Pakistani government has been in this respect."
He also hailed the government's ability to forge political consensus to take on extremists.
"No one I think would have predicted the political consensus that has emerged in Pakistan in terms of the effort to take on these extremists in the North West Frontier Province, in the Fata [Federally Administered Tribal Areas] and in that area."
Asked about reports that the Pakistani intelligence supported Taliban groups in their war against US and Nato forces in Afghanistan, Gates acknowledged that those relationships go back to the campaign against the Soviet occupation of Afghanistan in the 1980s.
However now "I believe we are in the same trench, working for the same goal," he said.

Copyright AFP (Agence France-Presse), 2009