KABUL, Afghanistan - An Afghan border policeman was killed in an exchange of fire with Pakistani troops along the country's contested eastern border, an Afghan security official said Thursday, in an incident that threatens to further inflame tensions.

Pakistani forces fired artillery rounds late Wednesday at Afghan border police in the Goshta district of Nangarhar province, according to Interior Ministry spokesman Sediq Sediqi. In an ensuing five-hour firefight, one border policeman was killed, he said.

Pakistan's government blamed Afghan forces for opening fire at a border post and described the incident as one of many "repeated violations" of the border. A statement said two Pakistani paramilitary soldiers were wounded.

"This is not the first time that the heavy fire was initiated from the Afghan side causing heavy injury and damage to the Pakistani structures," the Pakistani Foreign Office said. It added that the Afghan ambassador to Islamabad was summoned to the ministry and a complaint was filed.

Ties between the neighbors have been severely strained in recent months, and the mountainous region where the latest shooting took place has seen acrimonious exchanges between the two sides over the demarcation of their border.

A Western military official said the Pakistanis fired tank rounds into the Afghan side of the border as part of the exchange of fire. The official said it was not clear what started the skirmish, which was observed remotely by the U.S.-led coalition.