The latest incident of violence took place as army pushed ahead to clear the last rebel stronghold of Shawal valley in North Waziristan, contiguous to the Afghanistan border.
An official said that security forces were patrolling in the suburbs of Dattakhel when rebels targeted them with two remote control bombs, killing four soldiers and injuring four others.
In retaliation, the security forces killed 12 militants.
Dattakhel had been mostly cleared but being close to Shawal, militants still operate there.
According to intelligence reports, forces are slowly moving in the thickly forested and mountainous Shawal from North Waziristan and South Waziristan.
Once captured, it will destroy the last known sanctuary of militants in Pakistan.
Last month, armed forces cleared 95 per cent of Khyber tribal region including its inaccessible Tirah valley on the Afghan border.
