Pakistan today condemned as "cowardly" the killing of 11 of its soldiers on the Afghan border in an air strike by US-led forces in Afghanistan.
The attack "hit at the very basis of co-operation" between Pakistani and US-led forces in Afghanistan, the Pakistani military said.
The soldiers were killed at a border post in the Mohmand region, opposite Afghanistan's Kunar province, late on Tuesday.
A government official said last night a pilotless US drone was suspected to have fired a missile into the area.
The incident comes as concern has been rising in Kabul and among Western forces battling the Taliban in Afghanistan about Pakistani efforts to negotiate peace pacts to end militant violence on its side of the border.
A new Pakistani government has been negotiating with ethnic Pashtun tribes to get them to press militants in their areas to give up a campaign of violence in Pakistan in which hundreds of people have been killed over the past year.
Many al-Qaeda and Taliban militants took refuge on the Pakistani side of the border after US-led forces ousted the Taliban in Afghanistan in 2001.