A bomb attack on Monday wounded at least 10 Pakistani soldiers in the Taliban and al Qaeda hotspot of Waziristan on the Afghan border, officials said.
The device was detonated by remote control as a military vehicle passed through the Sararogha village area in the mountains of South Waziristan, which is part of Pakistan's semi-autonomous tribal district.
"At least 10 soldiers were wounded, three of them seriously," a security official told AFP.
A local intelligence official confirmed the bomb blast and casualties.
Pakistan carried out a sweeping offensive in 2009 in South Waziristan targeting the country's main Taliban faction, but many of their commanders and foot soldiers are believed to have fled to neighbouring North Waziristan.
Washington is pressing Islamabad to launch an all-out offensive in North Waziristan against the al Qaeda-linked Haqqani network, which is responsible for killing US troops in Afghanistan and to which Pakistani spies have close connections.
But relations between Islamabad and Washington plummeted after US commandos killed Osama bin Laden in Pakistan in May, and the military says it is too overstretched fighting Taliban elsewhere to open a new front in Waziristan.