Military officials say heavy fighting between Pakistani troops and militants has killed 23 soldiers and at least 110 enemy fighters at a flashpoint near the Afghan border.
The fighting, which began on April 5, followed weeks of clashes between rival Islamist militias to control strategic heights in Tirah, a remote valley in the Khyber tribal district bordering Afghanistan.
The officials, who spoke on condition of anonymity, said the military was also using jet fighters to strafe the rebel positions.
Khyber lies on the route of the NATO supply line into Afghanistan, used by U.S.-led troops to evacuate military equipment ahead of their 2014 withdrawal.
Officials also say it is key to protecting security in Peshawar for elections next month.
The area is cut off to journalists and aid workers.
Based on reporting by dpa and AP