The attacks by the Yemeni air force hit the vehicles on the outskirts of the town of Mahfad in Abyan province, the official said, speaking on condition of anonymity.
The official said Al-Qaeda-linked militants were seen evacuating the casualties and transferring them to a local medical centre.
Al-Qaeda militants remain active in Mahfad, close to Zinjibar and Jaar, which they ruled for a year before being driven out by a government offensive mounted in May 2012.
Al-Qaeda had taken advantage of a weakening of central government control during the 2011 uprising that forced veteran strongman Ali Abdullah Saleh from power to seize large swathes of the south and east.
Al-Qaeda in the Arabian Peninsula, which is based in Yemen, is considered by Washington as the most dangerous branch of the militant network.
