ISLAMABAD, Pakistan — A suicide car bomber attacked a prison van while gunmen torched six NATO oil tankers in separate strikes Saturday that killed four Pakistani police officers and wounded 10 others, authorities said.
The army, meanwhile, kept up its pressure on the Pakistani Taliban in the tribal belt, killing 20 suspected fighters, while apparent U.S. missiles killed five suspected insurgents in a nearby northwest region, officials said.
The oil tankers were hit in Chakwal district - a rare such assault in Punjab province. Militants and ordinary criminals frequently attack trucks that travel along supply routes used by NATO and U.S. forces in Afghanistan, but usually in the northwest Khyber-Pakhtoonkhwa or southwest Baluchistan provinces.
Suspected militants in two pickups rode up to the gas station where the tankers were parked and opened fire before setting the vehicles aflame, police officer Aslam Tareen said. Four police officers who responded to the scene were killed, he said.
The drivers of the oil tankers said they were headed for NATO troops in Afghanistan, Tareen said. The militants managed to flee. Chakwal is not far from the Punjab border with the northwest province.
On Saturday morning, a suicide car bomber targeted a prison van as it arrived at a jail in Timergarah to pick up prisoners to take to the nearby Swat Valley, senior police official Shakeel Khan said.
No prisoners were in the van at the time, but 10 police officials were wounded.
Timergarah is in Lower Dir district, near the Afghan border. It was a militant stronghold until spring 2009 when a military offensive there and in Swat largely reclaimed the areas from insurgents.
Pakistan followed that offensive with one in South Waziristan tribal region, a key haven for the Pakistani Taliban.
Many militants there have since fled to other areas such as Orakzai, another part of the lawless tribal belt bordering Afghanistan, leading the army to open new fronts.
Troops on Saturday raided a militant ammunition depot in Sangra village in Orakzai, killing 10 suspected insurgents, local administrator Jehanzeb Khan said. One soldier was wounded.
Airstrikes later destroyed three more hide-outs, killing another 10 suspects, Khan said.
The information is nearly impossible to verify independently - access to the tribal belt and regions such as Dir is difficult to obtain due to the dangerous, remote nature of the terrain and legal restrictions.
The U.S. has relied heavily on its covert campaign of missile strikes to take out targets in the tribal areas.
A suspected U.S. missile strike in the Machi Khel area of North Waziristan tribal region killed five suspected insurgents at a compound, said two intelligence officials who spoke on condition of anonymity.
Information for this article was contributed by Hussain Afzal, Rasool Dawar and Riaz Khan of The Associated Press.
Front Section, Pages 18 on 04/25/2010