The official says the bombing occurred on the edge of the town of Arsal in the Atta Valley today. He spoke on condition of anonymity in line with regulations.
The Islamic State group and al-Qaida's branch in Syria known as the Nusra Front control parts of that volatile border area.
The Nusra Front and IS abducted 29 soldiers and policemen in Arsal in 2014, when they briefly overran the town. Four of the soldiers have been killed in captivity.