Pakistani military jets pounded rebel hideouts in restive Swat valley in the northwest on Tuesday, killing at least 10 people and wounding dozens, a security official said.
The air strike came despite an offer of truce during the current Muslim fasting month of Ramadan announced by the government at the weekend.
A senior security official said fighter jets bombed Ghat Peochar area following intelligence that leaders of pro-Taliban cleric Mullah Fazlullah's group were hiding there.
"We are not sure if any leader was among 10 killed in the air strike," the official, who spoke on condition of anonymity, told AFP.
Chief military spokesman Major General Athar Abbas confirmed the bombing but said he did not have details of casualties.
Fazlullah's spokesman, Mulsim Khan, earlier on Tuesday claimed to be holding two Chinese telecoms engineers and their entourage who were kidnapped four days ago from neighbouring Dir district.
He claimed the latest air strike killed only civilians and that none of the group's fighters were hurt.
The engineers went missing along with their local driver and a security guard near the Afghan border where they had been checking an installation.
Fazlullah, who is also known as Mullah Radio for using illegal FM channels to propagate his ideas, has been leading a violent campaign to enforce hardline Islamic Sharia law in Swat valley since 2007.