Gen Petraeus praised Pakistani soldiers in South Waziristan
The regional US commander, David Petraeus, has urged Pakistan to step up pressure on the Afghan Taliban.
Gen Petraeus praised Pakistan's recent offensive against the Taliban in South Waziristan, but said it was mainly aimed at Pakistani groups, not Afghans.
The Afghan Taliban have used safe areas inside Pakistan to base themselves and launch cross-border attacks.
But Pakistan said it was cracking down on all militants, and that at least 22 had been killed near the Afghan border.
Gen Petraeus, the head of US Central Command and the man in overall charge of US military strategy in the region, said that to make significant progress in Afghanistan "it would be very helpful if additional pressure could be put [by Pakistan] on the leadership of the elements that are causing problems in Afghanistan".
The leaders of the Afghan insurgency are thought to be hiding out in Pakistan's tribal areas and its province of Balochistan, but Pakistan has so far been reluctant to launch major operations in these areas, says the BBC's security correspondent, Frank Gardner.
Nevertheless, a major offensive has been taking place in the Pakistani region of South Waziristan. Pakistan's Foreign Minister, Shah Mehmood Qureshi, said about 600 Taliban had been "eliminated" in that operation.
"We have put in a lot of pressure. And we intend to continue to do that," he said.
"For us, a terrorist is a terrorist, whether he operates on this side of the border or that side of the border," he added.
Gen Petraeus praised Pakistani operations, including that in South Waziristan.
"We think that the performance has been quite impressive," he said, noting that there had been significant losses, especially by Pakistani officers.
The army has captured territory in South Waziristan, a hotbed of Islamic militancy, but many insurgents are believed to have fled to nearby regions.
In fighting at the weekend in the tribal region of Kurram, which is near South Waziristan, 22 militants and five soldiers were reported to have been killed.
Gen Petraeus, speaking at a security conference in Bahrain, also said methods used by the US in Iraq were being tried in Afghanistan.
He said he hoped the US could form alliances with local forces in Afghanistan along the lines of the Awakening movements in Iraq, in which Sunni tribes had allied with the US against al-Qaeda.