ISLAMABAD: Taliban militants on Wednesday released a video showing severed heads of 17 Pakistani soldiers who they claimed to have killed in a cross-border attack on a check post in Pakistan.

The beheading, claimed by the Tehrik-i-Taliban Pakistan (TTP), took place on Sunday when Taliban militants from Afghanistan infiltrated into the northwestern district of Upper Dir.

A senior security official in the northwestern regional capital Peshawar on Wednesday confirmed to AFP that a total of 17 soldiers were targeted by the attackers who came from the eastern Afghan province of Kunar.

“Six troops were killed on the first day, then another seven were slaughtered the next day,” the official said.

“Four were missing and now they have also been beheaded,” he said.

Dir, a key border transit route, neighbours Swat valley where Pakistan defeated a local Taliban insurgency in 2009.

Intelligence officials blamed the attack on loyalists of Pakistani cleric Maulana Fazlullah, who fled to Afghanistan after losing control of Swat to the army.

The video prepared by the Taliban's media wing shows 17 severed heads of soldiers placed on a white sheet while masked men stand behind clutching assault rifles captured from the soldiers.

Local security officials confirmed that all the victims were Pakistani soldiers.

“God has given us a great victory, we have killed them all. Four of the heads you can see are from Frontier Corps (paramilitary force), the rest are from the army,” an unseen commentator said in the video.

The army said more than 100 militants “from a safe haven across the border” attacked troops on patrol. It claimed to have killed 14 militants.

The army “has strongly protested with their counterparts across the border for not taking action against miscreants present in safe havens in Afghanistan,” a military official said.

The foreign ministry summoned the deputy head of the Afghan mission to lodge a formal protest against “the intrusion of militants from the Afghan side into Pakistani territory,” officials said.

The Afghan diplomat was informed that “the government of Afghanistan should take appropriate measures to prevent the recurrence of similar incidents in the future,” it said.

Pakistani troops have for years been fighting local Taliban but have resisted US pressure to carry out a sweeping offensive against Afghan Taliban fighters in its North Waziristan tribal area.

Afghanistan and Pakistan have long blamed each other for Taliban violence plaguing both sides of their porous, mountainous border.

Pakistan says rebels have regrouped in eastern Afghanistan. Afghan and US officials want Pakistan to eliminate Taliban and al Qaeda-linked havens used to launch attacks in Afghanistan.