Two suicide bombers attacked the headquarters of a security force in northwestern Pakistan on Monday morning, killing at least three officers and wounding 11 others, police and rescue officials said.

The attack took place in Peshawar, the capital of Khyber Pakhtunkhwa province bordering Afghanistan, when security forces were preparing for the morning parade at the sprawling facility located in the heart of the city, said Peshawar Police Chief Saeed Ahmad.

He said one attacker detonated his explosives at the main gate of the provincial headquarters of the Federal Constabulary, while the second bomber was shot and killed by officers near the parking area.

According to Ahmad, about 150 security personnel were on open ground inside the headquarters for morning parade drills when the attack took place.

He said police had completed the clearance operation and authorities had collected samples of the body parts of the attackers for DNA tests.

He added police are still investigating to determine the identity and nationality of the attackers without giving further details.

AP video by Muhammad Arif

Production by Muhammad Farooq