Al-Qaida militants targeted a military camp in Yemen’s southern Abyan province, killing at least 20 troops and setting off hourslong clashes that lasted into early morning Friday, Yemeni officials and tribal leaders said.

The attack began around midnight, with militants firing rocket propelled grenades at the camp belonging to members of a Yemeni force trained by the United Arab Emirates, a member of the Saudi-led coalition fighting the Houthi rebels in Yemen since 2015.

The militants then overran the camp, seizing and confiscating equipment and weapons, before setting it on fire, according to the tribal leaders. There was no immediate claim of responsibility by Al Qaeda but the officials said the attack bore all the hallmarks of the Sunni militant group.

The attack came a day after the main southern city of Aden was shaken by double attacks. The Houthi rebels fired a missile at a military parade of the same UAE-trained militia known as the Security Belt while suicide bombers blasted a police station in another of the city’s neighborhoods.