At least 25 pro-Taliban militants were killed on Sunday as security forces, backed by helicopter gunships and artillery, took control of a strategic tunnel in northwestern Pakistan, which had been occupied by the extremists.

On Saturday, militants had occupied the Japanese-built Kohat tunnel near Darra Adam Khel town, after security forces launched a major operation in the area to trace four trucks carrying ammunition, which had been hijacked by the rebels.

Traffic between the key city of Kohat and Peshawar, the capital of the North West Frontier Province, had been blocked after the militants captured the tunnel. Scores of vehicles had been stranded on both sides of the tunnel.

"Twenty five militants have been killed," military spokesman Major General Athar Abbas said. Two security personnel were injured in today's clashes.

He said: "The tunnel is now under the control of the security forces."

Troops used artillery, helicopter gunships and heavy machine guns to evict militants holed up in bunkers on hills overlooking the tunnel.

On Wednesday, militants in Darra Adam Khel hijacked four trucks carrying supplies and ammunition for security forces in South Waziristan. Troops launched an operation to recover the trucks after a jirga or tribal council failed to resolve the issue through negotiations with the militants.

Over 60 militants and two security personnel have died in fighting in the region over the past few days. Darra Adam Khel is known for its weapons market and illicit arms manufacturing factories at which tribal gunsmiths produce replicas of even sophisticated weapons like AK-47 assault rifles. Reports have said the town is now a stronghold of the outlawed Lashkar-e-Jhangvi.

Abbas said there were several criminal gangs active in Darra Adam Khel and the security forces had asked the political administration to initiate a process through a jirga so that the civil administration could take full control of the area. The unrest in the region was due to the lack of assertiveness of the local administration, he said.

Officials also said that 50 militants, including 31 hardcore rebels, were arrested in the Matta region of the restive Swat valley in the NWFP.

The army said in a statement that a large quantity of arms and ammunition including rifles, pistols and shotguns were seized in Matta, Sambat and Bodi Garam. Life remained peaceful in other parts of Swat.

The army also said there were heavy exchanges of fire between security forces and militants at Ladha and Kot Kai in the South Waziristan tribal region, where troops are conducting a major operation against the followers of Pakistani Taliban commander Baitullah Mehsud