Yemeni security and military officials say a suspected U.S. drone strike killed four al-Qaida members travelling by car in the coastal city of Mukalla.

The officials say the airstrike took place on Friday night in Mukalla, the capital of Yemen's sprawling eastern Hadramawt province. The explosion was heard in some parts of the city.

Al-Qaida's Yemen branch, considered to be the most dangerous offshoot of the terror network, has made gains in the province and captured Mukalla earlier this year.

The officials say at least five other militants were wounded in the airstrike. The officials spoke on condition of anonymity because they are not authorized to talk to reporters.

Al-Qaida has profited from the turmoil that has engulfed Yemen and U.S. drones have continued to target top al-Qaida leaders there.