The air strikes were carried out in various areas of the Tirah valley in the lawless Khyber tribal district, where Taliban militants are active.
“At least 21 militants were killed and several injured while hideouts were destroyed in precise aerial strikes in various areas of the Tirah valley in Khyber,” a source told.
The strikes were part of a major offensive to clear Taliban and Al-Qaeda strongholds that began last year in North Waziristan, one of seven Pakistani tribal districts bordering Afghanistan.
The military began an offensive in Khyber in October 2014, carrying out air strikes and using artillery, mortars and ground troops.
Overall levels of militancy-linked violence have dropped dramatically this year, with 2015 on course for the fewest deaths among civilian and security forces since 2007 — the year the Pakistani Taliban umbrella group was formed.