Three policemen were killed in the first attack when a remote-controlled bomb destroyed a vehicle carrying police and paramilitary forces in Bannu district of troubled Khyber Pukhtunkhwa province, said Rafique Khan, a local police official.

Five security personnel were also wounded in the attack, said Khan, who blamed local militants but offered no evidence to back up his claim.

Also Thursday, a bomb ripped through a checkpoint manned by tribal police in Bara, a town near the northwestern city of Peshawar, killing one officer and wounding four others, police official Iqbal Khan said.

Militants with bases in the northwest have carried out scores of attacks on police and army targets over the last three years. They are seeking to overthrow the US-allied, democratically elected government and replace it with a pro-Taleban emirate.

Meanwhile, tribal rebels blew up a gas pipeline in the insurgency-hit southwestern province of Baluchistan early Thursday, cutting supplies to several areas in cold weather, officials said.

The pre-dawn blast damaged the main pipe bringing gas from Jafarabad district to the provincial capital Quetta and five other districts, Sui Southern Gas Company spokesman Inayatullah Ismail said.

“The gas supply to thousands of consumers has been suspended,” he said, adding that it could take two days to repair the pipeline.

Local police and security officials confirmed the attack, claimed by the Baluch Republican Army, a nationalist group.

Impoverished Baluchistan, which borders Iran and Afghanistan, has been wracked by an insurgency waged by ethnic Baluch tribes seeking more political rights and a greater share of profits from the region’s natural resources.

“We carried out the attack,” Sarbaz Baluch, a spokesman for the rebel group told local media.

“It is in retaliation for extrajudicial killings on our youth by the intelligence agencies,” he said.

Hundreds of people have died in violence ripping through the province since the insurgency flared in late 2004.

The region has also been hit by attacks blamed on Taleban militants, although sabotage of gas pipelines are a trademark of nationalist rebels.