A suicide attacker detonated a car bomb at a checkpoint in a northwestern Pakistan town on Saturday, killing at least 13 policemen and troops, officials said, with the toll expected to rise.

The attack on the security forces checkpoint took place in Doaba, a town in restive Hangu tribal district, an official said, not far from the Afghan border.

Earlier, a security official had said that five policemen were killed.

"The toll has risen to 13, mostly police and soldiers as a military convoy was also passing from the checkpost when the attacked occurred," another security official told AFP.

"The toll is likely to rise," the official said but did not give the number of injured people saying they were still gathering details.

"The attack occurred at 4.10pm (10.10 GMT)," a different official confirmed.

Security forces immediately cordoned off the area, which lies close to the lawless tribal areas of Pakistan, bordering Afghanistan.

There has been no claim for the attack and police have not been able to confirm the identity of the bomber.

Pakistani security troops are frequent targets for extremist militants who oppose the government's role in the US-led "war on terror" and more than 1500 government forces have been killed by insurgents since 2002.

Much of the violence has been concentrated in northwest Pakistan, where the army has been fighting hardline Taliban and Al-Qaeda extremists who fled the 2001 US-led invasion of neighbouring Afghanistan.

Taliban warlord Baitullah Mehsud has threatened to launch suicide attacks to avenge missile strikes by US drones on tribal areas targeting Islamist militants.

AFP

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