"I do not think that the money that we have spent in Pakistan has been a waste. The reality is that Pakistan now has 140,000 troops on the border. Their actions in Swat and in South Waziristan have been helpful to us," he said.

Gates spoke as two countries acknowledged differences since May 2 unilateral action that took out al-Qaeda leader Osama bin Laden from his hideout in Abbottabad.

The Pentagon leader's remarks also opposed the view by some Congressmen who want the Capitol Hill to cut down aid for Pakistan following bin Laden's discovery in the country.

"Our relationship with Pakistan is not what we wish it were. There is, as the Pakistanis are fond of pointing out, a deficit of trust, in their view because the United States has abandoned them on several occasions in the past; most recently, in 1990 and in 1989 after the Soviets left and then with the Pressler amendment," the defense secretary explained during an interaction at the American Enterprising Institute.

Continuing, Gates noted that the Obama administration "has made a significant effort to try and change the nature of our relationship with Pakistan, in terms of a more enduring partnership."

"And I would say that, obviously, the record is a mixed one. And we both have concerns, but there's also no doubt in my mind that we have to continue to make our best efforts to manage this relationship going forward," added Gates.

Pakistan, he said, is "very important, not just because of Afghanistan but because of its nuclear weapons, because of the importance of stability in the subcontinent."

"So we need to keep working at this," said Gates. Apart from fighting al-Qaeda and Taliban in the last several years, Pakistan also serves as the main land route for around 60 per cent of the supplies for Afghanistan-based NATO and US troops. It has strongly objected to the unilateral American action, which has also been followed by rise in revenge bombings.

Copyright APP (Associated Press of Pakistan), 2011