For much of the last decade, Saudi Arabia and the United Arab Emirates were portrayed as the twin pillars of Gulf security, united by common threats and shared ambitions. Nowhere was this partnership more visible than in Yemen, where both countries joined a military intervention in 2015 to counter the Iran-backed Houthi movement. That image of unity fractured dramatically in December 2025, when Saudi airstrikes hit Yemen’s southern port city of Mukalla — not against the Houthis, but against forces aligned with the UAE. The episode has laid bare long-standing divergences between Riyadh and Abu Dhabi and signals a dangerous new phase in Yemen’s already complex conflict.
The Mukalla Strikes: From Alliance to Accusation
The immediate trigger for the crisis was Saudi Arabia’s claim that it had targeted weapons shipments bound for the Southern Transitional Council (STC), a powerful southern Yemeni separatist group backed by the UAE. According to Riyadh, vessels arriving at Mukalla port had disabled tracking systems and unloaded arms, allegedly originating from Fujairah in the UAE. Abu Dhabi swiftly denied the allegations, insisting that the shipment was non-military and known in advance to Saudi authorities.
What made the episode extraordinary was not merely the airstrikes themselves, but their target. For the first time, Saudi Arabia openly used military force against a group closely linked to a fellow Gulf state. Within hours, the UAE announced the withdrawal of its remaining forces from Yemen, citing concerns over the viability and safety of its mission. A proxy rivalry that had simmered beneath the surface had suddenly become explicit.
The Southern Transitional Council: The Fault Line
At the heart of the Saudi–UAE rift lies the Southern Transitional Council. Established in 2017, the STC seeks to re-establish an independent South Yemen, which existed until unification with the north in 1990. With strong Emirati backing, the STC has steadily consolidated control over large parts of southern Yemen, including the interim capital Aden.
For Saudi Arabia, this poses a strategic dilemma. Riyadh supports Yemen’s internationally recognised Presidential Leadership Council, which claims sovereignty over the entire country. The STC’s growing power undermines this framework and challenges Saudi Arabia’s vision of a unified Yemen under a friendly central authority. In contrast, Abu Dhabi views the STC as a reliable local partner capable of securing ports, shipping lanes and counterterrorism objectives.
Why Hadramout Is a Red Line
The recent escalation is closely tied to developments in Hadramout, Yemen’s largest and resource-rich province. The STC’s expansion into Hadramout, including its influence over PetroMasila — Yemen’s largest oil company — has heightened Saudi anxieties. Control of Hadramout offers access to energy revenues, strategic depth and a long coastline along the Arabian Sea.
For Riyadh, the prospect of a UAE-aligned entity dominating Hadramout is deeply unsettling. It would place a rival-backed political force along Saudi Arabia’s southern flank, with leverage over energy assets and maritime routes. This explains why Saudi Arabia appears willing to escalate militarily despite the risks of confronting a former ally.
Diverging Endgames in Yemen
Although Saudi Arabia and the UAE entered the Yemen war together, their strategic objectives have diverged over time. Saudi Arabia’s overriding concern has been border security and the containment of Iranian influence via the Houthis. Abu Dhabi’s priorities have been more maritime and security-oriented: controlling key ports, protecting shipping lanes, and combating Islamist groups such as al-Qaeda in the Arabian Peninsula.
These divergent goals have led the two countries to back different Yemeni actors under the same anti-Houthi umbrella, turning coordination into