The US has asked Pakistani leaders participating in the strategic dialogue to accelerate the pace and take strong action against terrorist safe havens there, even as it appreciated Islamabad's role in the war against terrorism.

The Pakistani delegation were told that continued presence of the terrorist safe havens in the country would undermine the US-led international efforts against extremism in Afghanistan and in the region.

Identical messages were conveyed to the delegation at the State Department, at the White House when they met US President Barack Obama and to Pakistan Army chief Gen Kayani when he met defence secretary Robert Gates and chairman of the Joint Chiefs of Staff, Admiral Mike Mullen at the Pentagon.

Officials familiar with the discussions said that US conversations with the Pakistani leaders reflected the Obama administration's growing sense of frustration about the continued existence of these havens and their reluctance to take action against certain terrorist groups like the Haqqani network.

"We definitely recognise that there are safe havens in other parts of the region, including North Waziristan. And we will be encouraging Pakistan to take steps there as well," State Department spokesman P.J. Crowley told reporters.

Similarly, Pentagon spokesman Jeoff Morrell told reporters that Gates-Kayani meeting felt the need to have better coordination along the Afghanistan-Pakistan border.

"We've been doing a much, much better job of that for many, many months now," he said, "but this incident clearly indicates there is more work to be done, and there was a resolve and commitment to do the hard work that it takes to better coordinate our actions on both sides of the border."

The meeting lasted for 30 minutes. Gates repeated Washington's regret over the deaths of Pakistani soldiers during a helicopter attack along the Pakistan border, and "expressed his condolences to the families" of the soldiers who died, Morrell said.

The defence secretary stressed that the shooting of the border guards was "unintentional" and that the American military was working with the Pakistanis to make sure it never happens again. There is no secret that there are "activities" that move across borders between the tribal areas and Afghanistan, Crowley said, adding that is why the strategy is focused on effective action on both sides of the border.

"We understand that Pakistan, you know, has a variety of challenges. They've got, you know, capacity issues. Some of this effort given the strength of the Pakistan military, as arguably the strongest institution of government within Pakistan, it has been forced to shift its attention from fighting extremism within its borders to cope with the impact of the flood," he said.

"Among the issues that we'll be discussing with Pakistan this week are how we can continue to work with Pakistan and increase its capabilities so that it can do multiple things at the same time. But clearly while we've seen aggressive action by Pakistan in recent months, more does need to be done. There are still safe havens within its territory that need to be addressed," the State Department spokesman added.