The commander of US forces in Afghanistan has expressed concern at Pakistan's strategy against foreign al-Qaeda and Taleban fighters.
General Barno said Pakistan should continue military action
Lieutenant-General David Barno said Pakistan must eliminate a "significant number" of militants along the border.
"There are foreign fighters in those tribal areas who will have to be killed or captured," he said.
Pakistan says foreign fighters can stay in the region if they renounce terrorism and live peacefully.
However, General Barno said attempts to reconcile the foreign militants would fail.
"It's very important that the Pakistani military continue with their operations to go after the foreign fighters in particular,
who in my view will not be reconciled," he told the Associated Press.
"We have some concerns that [the strategy] could go in the wrong directions."
On Friday, Pakistan extended a deadline for foreign militants to give themselves up to authorities after no one surrendered.
The army had threatened the fighters with a renewed offensive but military spokesman Shaukat Sultan said the political process should be given another chance.
An offensive in South Waziristan last month left more than 100 troops and militants dead, the military says.
It was the largest army operation in the tribal areas since Pakistani independence in 1947.
Hundreds of foreign militants are believed to be sheltering in the region, with the aid of some Pakistani tribesmen.
Pakistan recently granted an amnesty to five tribesmen accused of sheltering foreigners.