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, pitting factions battling the Iran-backed Houthi movement in the country's decade-long civil war against each other and deepening a rift between Saudi Arabia and the UAE. STC-aligned forces have in recent years taken control of much of the south, which they want once again to be an independent state, by pushing out forces loyal to the internationally recognised government and the Presidential Leadership Council overseeing it.