A suicide car bomber and accompanying gunmen struck a police facility in northwestern Pakistan on Friday, killing at least 16 people – including five police officers – during prayers at a mosque, officials have said.

The vehicle rammed into an outer ⁠wall of the police facility in Khyber Pakhtunkhwa province’s Kohat city, provincial police chief Zulfikar Hameed was reported as saying. “It was a suicide attack,” he added.

Police personnel, their family members, and other civilians were offering Friday prayers at the mosque when the attackers struck. The explosion damaged the mosque and nearby structures, and created a crater in the area, reports said.

Security forces were engaged in a gun battle with the attackers and one assailant wearing an explosives-vest was killed, the police said in a statement.

No group has claimed responsibility for the blast. Pakistani President Asif Ali Zardari and Prime Minister Shehbaz Sharif expressed grief over the casualties.

Militant attacks have risen in Pakistan’s border areas in recent months, with violence flaring up after each attack. Fifteen police officers were killed in a similar car bombing and ambush in Bannu in the Khyber Pakhtunkhwa province in May.

Islamabad has accused Afghanistan of hosting the militants and the Pakistani military has launched attacks inside Afghanistan in response. Kabul, however, says the strikes are hitting civilians, including women and children.

The bombing of a mosque in Islamabad in February killed more than 30 people, and in March, a Pakistani attack on a drug rehabilitation center in Kabul killed hundreds, according to Afghan officials.