Yemeni military officials say two militants were killed when a missile launched from a drone aircraft hit their vehicle.

The officials didn't say who launched the Tuesday airstrike.

U.S. drones have often carried out attacks against al-Qaida suspects in Yemen. The U.S. considers the local branch the world's most dangerous.

The officials said the airstrike targeted two vehicles traveling in the desert between Marib and Hadramawt provinces in eastern Yemen, killing two men in one of them. The officials had no information on casualties in the second car.

Yemen's rugged desert and mountain areas have provided a safe haven for al-Qaida militants.

A government campaign against the group has been met with violent retaliation.

The officials spoke on condition of anonymity because they were not authorized to speak to reporters.