QUETTA: Suspected militants killed four policemen in Balochistan's troubled Naseerabad district on Thursday evening, police said.

A police official who requested anonymity since he was not authorised to speak to media told Dawn that suspected militants opened indiscriminate fire on a patrolling police van in Chahtar area of Naseerabad district.

"All four policemen received multiple bullet wounds and died on the spot", he said.

The militants sped away on their motorcycles after the attack.

A huge contingent of police was called from Dera Murad Jamali, the head quarter of Naseerabad district to launch a search operation against the assailants.

The police official said that an exchange of fire also took place between the militants and the additional contingent of policemen approaching the attack site.

The dead bodies were shifted to civil hospital Dera Murad Jamali where a large number of people had turned up.

There was no immediate claim of responsibility for the attack.

However, the police sources suspected the involvement of defunct Baloch militant group, Baloch Republican Army, in the attack.

Chahtar tehsil of Balochistan's Naseerabad district is considered to be one of the strong holds of Baloch militants.

Militants have been targeting vital national installations and security forces in the area during the past eight years.