Al-Qaeda attacked Yemeni separatist troops in the country's south overnight, killing two, the separatists and a security source said on Monday.

The attack targeted the Southern Armed Forces affiliated with the separatist Southern Transitional Council in Abyan governorate during a patrol operation, when the militants struck a vehicle, the council said in a statement.

Al-Qaeda in the Arabian Peninsula (AQAP), based in war-torn Yemen's south, is considered by Washington as the Sunni extremist network's most dangerous branch, after claiming high-profile attacks in the United States and Europe.

A security official told AFP that five others were wounded in the attack, speaking on condition of anonymity because he wasn't authorised to release the information.

The attack by AQAP is its first since Saad al-Awlaki took over leadership of the group after the death of his predecessor, Khalid Batarfi.