Pakistani warplanes resumed strikes against militant hideouts in South Waziristan on Saturday, security officials said, with more than 30 insurgents killed in the Afghan border tribal region in the past 24 hours.
After securing much of the scenic Swat Valley in the past month, the military plans to extend its offensive with operations in South Waziristan against the main stronghold of Pakistani Taliban leader Baitullah Mehsud, a key al Qaeda ally.
The operations came after Taliban gains in the region raised fears for the future of nuclear-armed Pakistan, a vital ally for the United States as it strives to defeat al Qaeda and stabilise neighbouring Afghanistan.
A full-scale offensive has not yet begun in South Waziristan but fighter jets have been softening up targets for the past several days.
"Our jet fighters bombed and destroyed two militant hideouts in Maula Khan Sarai," a security official in the region said, referring to a militant-held area east of South Waziristan's main town of Wana.
He gave no other details but an intelligence official said 15 militants were killed in those strikes.
On Friday, jet fighters killed more than 30 militants in attacks in the South Waziristan villages of Barwand, Sarwaki and Kundsari, said security officials who asked not be identified.
The military was not available for comment on those incidents and there was no independent verification of the casualties.
In a statement released on Saturday, the military said 32 insurgents were killed when armed forces retaliated after militants blocked a road between the towns of Tanai and Sarwaki in South Waziristan.
It was not immediately clear if those insurgent casualties were separate to those in Friday's air strikes.
Pakistani troops are near the end of the offensive, launched in late April, in the Swat valley and surrounding areas northwest of Islamabad. More than 1,300 militants have been killed in those operations, according to the military.
The start of the campaign against Mehsud will likely further reassure Western allies who see Pakistan as vital for their campaign to eliminate al Qaeda and Taliban in Afghanistan but who in the past have voiced concern about Islamabad's commitment to the fight against militancy.
Waziristan has long been regarded as a militant sanctuary and military experts see the showdown in South Waziristan as a possible watershed for al Qaeda and its allies.
About 2 million people have fled the fighting in northwest Pakistan. The exodus grew with the start of the Swat campaign and the prospect of more abandoning their homes with new fighting in Waziristan will add to fears of a humanitarian crisis.
The military offensive in the northwest has widespread support among most political parties and members of the public, but that backing could wane if the displaced are seen to be suffering unduly.
(Writing by Augustine Anthony; Editing by Paul Tait)