The move is likely to intensify tensions between troubled allies Islamabad and Washington, currently involved in difficult talks to repair ties.
More than 100 militants based in Afghanistan’s Kunar province entered Pakistan and attacked a military patrol on Sunday, the military official said. Fourteen militants and six soldiers were killed in the skirmish.
Seven Pakistani soldiers were beheaded by militants after the clash and four were still missing, the official said.
Foreign Ministry said the Afghan deputy head of mission in Islamabad was summoned and presented with a “strong protest”.
The Malakand faction of the Taliban claimed responsibility, and threatened more attacks.