The official further added that five Levies personnel were patrolling in Garigal area when the vehicle was targeted with a remote-controlled explosive device.
Local security officials confirmed the attack and casualties.
The blast occurred in remote Bajur agency tribal region, one of the seven semi-autonomous tribal areas in Pakistan, targeting a top tribal administration official's vehicle, Bajaur Agency Assistant Administrator Aanwar-ul-Haq told Anadolu Agency.
Back in June 2014, the army launched a full-scale offensive in mountainous North Waziristan, part of which constitutes FATA, aimed at wiping out militant bases in the highly volatile tribal region.
On August 11, a powerful bomb blast killed at least three people and wounded more than 20 others in the Char Mang district of Bajaur, authorities said.
It was against this backdrop that acting United States Special Representative for Afghanistan and Pakistan Alice Wells' scheduled trip to Pakistan was postponed last month at the request of the government of Pakistan.
The militant violence has killed tens of thousands of Pakistanis over the years.