Islamabad: Five soldiers died and more than 10 militants were killed in a clash on Sunday night along the border with Afghanistan, Pakistan’s military has said.

The firefight occurred when “terrorists from across the border attempted a physical attack on three Pakistan border posts in Mohmand Agency” tribal area in the northwest, an Inter-Services Public Relations (ISPR) statement said on Monday.

Islamabad said it had lodged a “strong protest” with the Afghan government over the incident.

“In [the] exchange of fire five soldiers embraced Shahadat [martyrdom]. Over 10 terrorists reported killed,” the statement said.

The slain soldiers were identified as Naik Sanaullah, Naik Safdar, Sepoy Altaf, Sepoy Nek Mohammad and Sepoy Anwar.

The foreign ministry said in a statement the government of Pakistan had launched a “strong protest” with the Afghan government over the killing of five soldiers in Mohmand Agency and one soldier in neighbouring Khyber agency tribal area as a result of “firing by terrorists from Afghan territory.”

The Afghan deputy head of mission was summoned the Foreign Office on Monday, where Pakistan conveyed its “grave concern” over the incident, it said.

“The Afghan government was urged to thoroughly investigate the incidents and take firm action against the terrorists operating from its soil to prevent recurrence of such incidents,” the ministry statement said.

Officials emphasised that cooperation from the Afghan side was important to prevent cross-border movement of terrorists and militants, the statement said.

Chief of Army Staff General Qamar Javed Bajwa appreciated the response by Pakistani troops to the militant attack in Mohmand Agency.

“Terrorists are [a] common threat and must be denied freedom of movement/action along the border,” the ISPR quoted the army chief as saying. Gen Bajwa emphasised the need for physical presence of troops on Afghan side of the border for “matching and effective border security”.

The army chief hailed the slain soldiers’ sacrifice.

The latest incident comes at a time when bilateral relations between Afghanistan and Pakistan are strained, following a wave of militant attacks in Pakistan in which more than 100 people were killed last month.

Pakistan sealed its border with Afghanistan on February 16 and held Afghanistan-based militant groups responsible for carrying out the attacks within its territory.

The Pakistan army later reportedly targeted militant hideouts close to the border, including a training camp of Jamaat-ul-Ahrar, an outlawed outfit which claimed responsibility for the February 13 suicide bombing in Lahore and the February 15 suicide attack on the headquarters of the Mohmand Agency’s political administration.

The army had asked Kabul to take action against 76 Pakistani militants operating from Afghan territory or hand them over to Pakistan so that they could be tried for their involvement in “terror-related activities”.

In response, Afghanistan delivered a list of 85 Taliban and Haqqani Network leaders and 32 terror camps on Pakistani soil, which it claimed were involved in “crimes against people of Afghanistan”.

Mohmand is one of Pakistan’s seven federally administered tribal districts near the Afghan border. Cross-border movements of militants both ways have been a major area of concern.

Many militants belonging to banned Tehreek-e-Taliban Pakistan (TTP) and other group had fled and taken refuge in Afghan border areas when a military operation was launched in June 2014 to clear the tribal region of militants and dismantle their infrastructure.