At least 10 Pakistani soldiers and 23 militants were killed in the clash in the remote Tirah Valley in the Bara area of Khyber, near the Afghanistan border.
"Dozens of militants attacked three recently established security checkpoints. That led to heavy fighting," a military official told Reuters, requesting anonymity because he is not authorized to speak to the media.
In the Orakzai tribal region, south of Khyber, Pakistani fighter jets bombed two militant hideouts, killing 15 militants and wounding 12, security officials in Orakzai said.
Casualties could not be independently verified, and militants often dispute official accounts.
Several Pakistani military offensives in the tribal regions such as Khyber have failed to crush militant groups.
The insurgency is led by the Pakistani Taleban, formally known as the Tehrik-e-Taleban Pakistan, which has an active faction in Khyber.
The military campaign along the entire border region and across several tribal agencies involves more than 100,000 Pakistani troops, but it has effectively reached a stalemate in many areas.
Formed in 2007, the TTP is an umbrella organization of militant groups allied with the Afghan Taleban and Al-Qaeda. It pledged to overthrow the Pakistani government after the military stepped up operations against militants five years ago.
Khyber is one of seven ethnic Pashtun tribal regions along the porous border which have never come under the full control of the state. Militants have taken advantage of the area's lawlessness to set up strongholds.
Khyber is one of the main land supply routes to Afghanistan for US-led NATO troops, suspended by Pakistan after a cross-border clash in November last year that left 24 Pakistani soldiers dead.
