A suspected U.S. drone strike has killed two al-Qaida militants in a car in Yemen's south, a Yemeni official said Tuesday.

Yemen's military has been on a weeks-long offensive to uproot al-Qaida from strongholds captured during Yemen's yearlong internal political turmoil. The U.S. has been helping, as it considers al-Qaida's Yemen branch to be group's most dangerous.

The official told The Associated Press by telephone from Shaba that the two militants were known for ties to al-Qaida and provided shelter for militants. Tribal officials there said four militants were killed. They spoke on condition of anonymity for fear of reprisals.

The official, speaking on condition of anonymity according to regulations, said the car took a direct hit and burst into flames. He identified the militants as Hussein Ruby and Fahd al-Horthy.