The attacker struck near an army communications center in Kohat, about 30 miles from the city of Peshawar. Army spokesman Maj. Gen. Waheed Arshad said nine troops were killed and four were wounded.
Pakistan has suffered a string of suicide attacks in recent days, most of them targeting security forces.
No one has claimed responsibility for the attacks, but officials blame militants linked to the Taliban and al-Qaida who have expanded their influence in areas near the Afghan border.
