The target of the bombing was the remote Tirah Valley, considered as the hotbed of Lashkar-e-Islam militants who are an ally of Taliban and al-Qaeda.
A security official said that heavy artillery fire was used to destroy four hideouts of militants.
According to initial reports, five militants were killed, he said.
The attack was part of ongoing Khyber-I operation launched in the district last month.
Khyber I’s main aim is to clear the areas lying from Bara Tehsil until the border of Tirah valley, following which a second phase of the operation would be launched.
Security forces have intensified their efforts to counter militants in Khyber.
Scores of families have been moved to safer places as the offensive against militant groups is picking up.
Khyber is among Pakistan’s seven semi-autonomous tribal districts near the Afghan border, rife with homegrown insurgents and foreign militants. These are also home to religious extremist organisations including al-Qaeda.
The plains of Bara hold strategic significance for militant groups as they connect the agency to the outskirts of Peshawar.
The area was being used by militants to put pressure on the provincial capital. In recent weeks, police and military posts in and around Peshawar have come under attack.
The key area also straddles the NATO supply line into Afghanistan.