At least nine Pakistani servicemen were killed on Sunday when a roadside bomb hit an army convoy passing through the troubled region of North Waziristan near Pakistan's border with Afghanistan, security sources said.
Militant groups including the Taliban and al Qaeda operate in the volatile tribal region, often launching attacks on troops and civilians from mountain hideouts on the porous border.
Initially, army sources said three soldiers had been killed but later a security official in the regional town of Miranshah raised the death toll to nine. At least 21 soldiers were wounded.
U.S. drone strikes often target insurgents in lawless and inaccessible North Waziristan, home to both homegrown and foreign militants.
On Saturday, at least three foreign militants were killed in a suspected U.S. drone strike in the Mir Ali area of North Waziristan, local officials said. Pakistan, which opposes the pilotless attacks, condemned the latest strike.