Security forces foiled the raid on the isolated check post, located at Serai Norang area in Lakki Marwat district of Khyber-Pakhtunkhwa province, after an intense gun battle that continued for over three hours rpt hours.
The militants, who were armed with rocket-propelled grenades, launched the assault shortly before 4 AM.
"Twelve terrorists were killed. The bodies of four terrorists, of whom two were wearing suicide jackets, are in the custody of the security forces," said a security official who did not want to be named.
Six personnel of the Frontier Constabulary were killed and eight more were injured.
The injured personnel were taken to military hospitals in Bannu and Peshawar, the official said.
Ten members of the same family were killed when a rocket fired by the militants hit a house near the check post, police officials told the media.
The militants also stormed into the home of a 'patwari' and killed two persons, they said.
Tehrik-e-Taliban Pakistan spokesman Ihsanullah Ihsan claimed responsibility for the attack. He claimed four suicide bombers were involved in the assault.
Ihsan said the attack was carried out in retaliation for the death of two Taliban commanders in recent US drone strikes.