TEHRAN, Feb. 12 (MNA) – At least four soldiers were killed and 22 others, including employees of a petroleum company, were injured in a suicide attack in Pakistan's restive northwestern region on Saturday, police said.

The incident happened in the country's North Waziristan tribal district when the suicide bomber riding a tri-wheeler laden with a bomb hit the vehicle of security forces that were escorting employees of a petroleum company.

“The suicide bomber riding a tri-wheeler hit the vehicle of the security forces on duty with MPCL Petroleum Company in Khajori Chowk in North Waziristan tribal district bordering Afghanistan. Four soldiers were killed and 22 others which included 15 employees of the company were injured,” a senior police official said.

The employees of Petroleum Company were on their way back to their resting place under tight security after duty hours when the bomber ambushed one of the force's vehicle escorting them, Economist Times reported.

The MPCL Company is engaged in the exploration of oil in the area.

MNA/PR