Al-Qaeda fighters in Yemen have killed at least 20 soldiers aligned with Yemen’s southern separatists.

According to a military spokesman, the attack occurred in the Abyan province at a security checkpoint in the Ahwar district. The spokesman added that the attack involved the use of rocket-propelled grenades, light and medium weapons, and military vehicles.

A senior leader of the separatist group, commander Yasser Nasser Shaye was killed in the attacks along with “a number of his companions.”

This comes as Yemen’s main southern separatist group STC, which is backed by the United Arab Emirates, expanded its presence throughout the southern Abyan province last month. The separatists say the move was to combat “terrorist organizations,” singling out al-Qaeda.

Yemen-based al-Qaeda in the Arabian Peninsula (AQAP) has used the conflict between a Saudi-led coalition and the Iran-aligned Houthis to enhance its influence.