Pakistani military jests have bombed suspected Taliban positions in North Waziristan, killing at least 25 people, following a wave of Taliban attacks against security forces.
A military official said 25 militants had been killed in the air strikes in the tribal area bordering Afghanistan after at least 20 soldiers were killed in an ambush on an army convoy.
There were conflicting claims about who was killed in the air strikes which took place in North Waziristan, a stronghold of the Pakistani Taliban as well as other militant groups.
While the military official said the strikes targeted militants, at least two residents reached by news agency AP in North Waziristan said civilians were among those killed in the air strikes.
They said many residents slept in the open out of fear their homes might be hit.
The Pakistani Taliban have vowed to step up attacks after their leader Hakimullah Mehsud was killed in a US drone strike in November.
The air strikes started at around 00:30 local time, another official told AFP news agency, adding that helicopter gunships also took part.
An intelligence official in North Waziristan's central town of Miranshah also told AFP that the air strikes were still going on and residents had had to flee.
The area where airstrikes occurred is remote and dangerous for journalists to access, making it impossible to independently verify the conflicting casualty claims.
The overnight strikes came after two days of attacks claimed by the Pakistani Taliban killed 34 security personnel. On Sunday, a bomb planted in a vehicle killed 26 troops inside an army compound in the northwest just before their convoy was to head into North Waziristan. And again on Monday, a suicide bomber killed 13 people, including eight security personnel in Rawalpindi, a garrison city near the capital Islamabad.
Prime Minister Nawaz Sharif cancelled his trip to the World Economic Forum in Davos after Sunday's attack.
Earlier in December, the Pakistan military had attacked militant targets in North Waziristan with artillery fire and helicopter gunships.
The violence has put pressure on Prime Minister Sharif to show he's doing something to address the violence that has plagued Pakistan for years.
Sharif has repeatedly expressed his desire to negotiate with militants instead of using military force to subdue them, but so far the Pakistani Taliban have shown little desire to negotiate with Sharif's government.
The new leader of the Pakistani Taliban, Mullah Fazlullah, has vowed to continue attacks against Pakistani forces.