A new bout of fighting erupted on Monday in a border area between Afghanistan and Pakistan, the latest indication of a sharp deterioration in relations between the important US allies.
Pakistan is seen as vital in bringing stability to Afghanistan as most Western forces prepare to withdraw by the end of next year.
The United States and other powers involved in Afghanistan have been trying to promote cooperation between the Asian neighbours, who have a history of mistrust.
Afghan officials said the clash on Monday erupted after Pakistani troops tried to repair a gate on the border, in the Afghan district of Goshta, where last week an Afghan border policeman was killed in an exchange of fire.
It is unclear if there were any casualties on Monday.