Khwarij attempted to enter Pakistan but their plan got failed in North Wazisrtan District.
Security forces foiled their attempt, killing 13 of them.
Three suicide bombers detonated themselves after coming under fire from troops.
During the operation, five soldiers embraced shahadat during the engagement, while one sustained minor injuries.
Earlier, six people were killed when unidentified assailants opened fire on a vehicle at Mir Ali tehsil in the tribal district North Waziristan.
District Police Officer (DPO) Waqar Ahmed Khan confirmed the incident, stating that all six occupants of the vehicle were burned to death.
The motive behind the attack could not be known.
According to reports, forces have launched a search operation to arrest the attackers.