Yemeni tribal and security officials say a missile fired by a suspected U.S. drone has killed three al-Qaida militants who were driving in a vehicle in the country's south.

They say the operatives were killed when an unmanned aircraft targeted their vehicle late Monday in the province of Shabwa.

The officials spoke on condition of anonymity because they weren't authorized to speak to the press.

Al-Qaida in the Arabian Peninsula, as the Yemen affiliate is known, has long been considered the global network's most dangerous branch, and has been implicated in a number of attempted attacks on the U.S. homeland.

Yemen was plunged into civil war more than three years ago. Al-Qaida and an Islamic State affiliate have exploited the chaos to expand their presence.