The Pakistan army said on Monday it had launched an air and ground offensive in Kurram region on the Afghan border, its first major military operation since the May 2 killing of Osama bin Laden.
Army spokesman Major General Athar Abbas gave few details of the operation in Kurram -- a tribal region which had become increasingly used as a refuge for al Qaeda-linked militants.
But he said the offensive aimed to reopen the road to Parachinar, a town on the Afghan border which has been cut off from the rest of Pakistan and facing increasing attacks from militants.
Many of those militants had fled from North Waziristan following an intense campaign of drone bombing by the United States.
The Afghan Taliban faction, the Haqqani network, had been involved in securing a peace deal for Kurram last year between militants and local Shi'ite tribesmen, security officials and tribesmen said at the time.
But that deal fell apart as locals complained of growing attacks and isolation from the rest of the country.
"The operation has been launched with the aim of clearing the region of militants who have indulged in kidnapping and suicide attacks on security installations and forces there," military spokesman Abbas said.
The offensive came days after a senior militant commander in Kurram deserted from the Pakistani Taliban.
Commander Fazal Saeed Haqqani, who was close to the Haqqani network but not from the same group, said he disagreed with attacks on Pakistani security forces and civilians.
The United States has been pushing Pakistan to step up its fight against militants since American special forces found and killed bin Laden in the Pakistani town of Abbottabad on May 2.