Gunmen on Wednesday killed four paramilitary policemen in an ambush in Balochistan, officials said.

The Pakistani Taliban said it carried out the attack , the second time this month it has claimed a deadly assault on security forces.

The Frontier Constabulary officers were attacked while patrolling a railway line in the provincial capital Quetta .

The victims had no chance to retaliate, said Abdul Razzaq Cheema, a senior police official, adding that they recovered 108 Kalashnikov bullet cases from the site.

"We suspect the attackers were at least four people who came on two motorbikes," he said.

A senior official of the paramilitary force confirmed the attack and toll.

On February 3 a suicide bomber killed 11 soldiers in an attack on an army camp in the Swat Valley in the northwest, with the Pakistani Taliban claiming responsibility.

For more than a decade police and troops have been battling Islamist militants and separatist groups in mineral-rich Balochistan, which borders Iran and Afghanistan.