At least 55 militants were killed in airstrikes and a gun battle with ground forces in Pakistan's troubled northwest where the military launched a major offensive this year, officials said Saturday.

The army intensified its offensive after the massacre of 150 people in a school in Peshawar this month, a carnage which Pakistan described as its own "mini 9/11" and a game-changer in the fight against extremism.

Troops raided a militant hideout late Friday in an area adjoining Orakzai and Khyber tribal districts -- near the Afghan border -- where the insurgents had gathered for a meeting, the military said in a statement.

"An intense battle took place, in which 16 terrorists were killed and 20 injured," it said, adding that "fleeing terrorists left behind nine dead bodies of their accomplices".

Troops arrested two critically wounded militants while four soldiers were also wounded in the battle, the statement said.

Separately, 39 militants, including two rebel commanders, were killed in airstrikes in the northwest late Friday and an ammunition depot was also destroyed, according to military spokesman Major General Asim Bajwa.

It was not possible to independently verify the casualties as media are banned from visiting the far-flung area.

In another incident, police said they arrested an important Taliban commander who was wanted for attacks on police and was also involved in the killing a local journalist in northwestern Khyber Pakhtunkhwa province.

The army has been waging a major offensive against longstanding Taliban and other militant strongholds in the restive tribal areas on the Afghan border for the last six months.

The offensive gathered momentum after the December 16 attack on an army-run school in Peshawar which killed 150 people, 134 of them children.

The Pakistani military says it has killed more than 1,700 militants so far in its heavy offensive in the tribal zone, with 126 soldiers having lost their lives.