Pakistan shut a key border gate with Afghanistan after clashes between guards killed at least four Pakistani soldiers and 12 militants on Wednesday.

A "large group of terrorists equipped with latest weapons" attacked two military posts near Kalash, Chitral district, the military said in a statement, adding that the "intense exchange of fire" led to the casualties, and a combing operation was underway in the area.

The press release said the movement and concentration of terrorists in several areas of Nuristan and Kunar provinces of Afghanistan had already been noticed, and leads were timely shared with the interim Taliban administration in Kabul.

The interim Afghan government "is expected to fulfill its obligations and deny the use of Afghan soil by terrorists for perpetrating acts of terrorism against Pakistan," it added.

Officials did not give any details about the insurgents but suggested they have links to neighboring Afghanistan. The statement said Pakistan expects the Taliban government in Afghanistan "to fulfill its obligations and deny the use of Afghan soil by terrorists for perpetuating acts of terrorism against Pakistan."

Previous such attacks have been carried out by Pakistani Taliban, known as Tehrik-e-Taliban Pakistan, and who have intensified attacks over the past months on Pakistan security forces. They are a separate group but an ally of the Afghan Taliban.

Separately, a mortar fire hit a house in Pakistan near the Afghan border, killing five Pakistanis- a mother and her four children. It was not immediately clear who fired the mortar and police were investigating the attack in the North Waziristan district of Khyber Pakhtunkhwa province, local authorities said.

Militants often target security forces deployed in the region with mortars, which also has caused civilian casualties in recent years.

The exchange of fire across the border also took place in the province, in the town of Torkham, and it was not immediately clear what prompted the gunfire, said Nasrullah Khan, an official in Torkham. He said Pakistani government and military officials contacted Afghan counterparts to defuse tensions.

Abdul Mateen Qani, a spokesman for Afghanistan’s Interior Ministry, confirmed the clash between Afghan and Pakistani forces. He said officials from both sides were trying to find the cause and seeking ways to prevent such clashes.

Pakistani authorities said dozens of trucks carrying perishable items, including vegetables and fruits, were waiting on both sides of the border for the reopening of the Torkham crossing, which is a vital commercial artery and a trade route to Central Asian countries for Pakistan.

The border closure came two days after caretaker Pakistani Prime Minister Anwaar-ul-Haq Kakar said U.S. military equipment left behind during the American withdrawal from Afghanistan had fallen into militant hands and made its way to the Pakistani Taliban, who are allied with the Taliban in Afghanistan.

The Afghan Taliban overran Afghanistan in August 2021 as U.S. and NATO troops were in the last weeks of a chaotic pullout from the country after 20 years of war.

The Pakistani Taliban have released statements and video clips in recent months claiming they possess weapons such as guns with laser and thermal imaging systems.

Torkham witnessed previous clashes in February and the town remained closed for several days after the two sides accused each other of trying to build new posts along the border in February.

According to the Pakistan-Afghanistan Joint Chamber of Commerce and Industry, the clashes at the time caused millions in losses to traders whose perishable goods were ruined.

Afghanistan has never recognized the porous border that runs through the Pashtun heartland and dilutes the power of Afghanistan’s largest ethnic group on both sides.

Pakistan says it has completed fencing along 97% of the border to stop cross-border attacks and smuggling. Pakistan also accuses the Afghan Taliban of providing sanctuaries to Pakistani militants who are living in Afghanistan.

In November 2022, the Pakistani Taliban ended a monthslong cease-fire with the government in Islamabad, ordering its fighters to resume attacks across the country.