The Saudi-backed presidential council in Yemen has expelled the leader of a separatist group and charged him with treason after he failed to fly to Riyadh for talks. Six other members of the presidency accused Aidarous al-Zubaidi, head of the United Arab Emirates-backed Southern Transitional Council (STC), of undermining the independence of the republic. A Saudi-led military coalition said Zubaidi fled after not joining STC officials on a flight from Aden and moved a large force to al-Dahle province. Coalition aircraft launched strikes on the forces in response, it added. The STC said the strikes, which reportedly killed four people, were unjustified and that Zubaidi was still in Aden. It also expressed concern that contact had been lost with the group's delegation in Riyadh. The past few weeks have seen southern Yemen moving to the brink of a new conflict, as various factions battle against Iran-backed Houthi forces in the civil war.