Yemen's future hangs in the balance after a dramatic turn of events in the south which have brought Saudi Arabia and the United Arab Emirates into unprecedented direct confrontation and threaten the country with partition.
Both Gulf powers have intervened on behalf of Yemen's internationally recognised government in the country's long-running civil war, but a fracturing of the alliance has seen them backing different rival groups on the ground, one of whom is now pushing to declare the independence of a breakaway state in southern Yemen.
On Friday, the UAE-backed force declared that a war had begun, accusing Saudi-backed ground forces of launching an attack alongside air strikes by the Saudi air force.
Yemen's civil war broke out in 2014 and has plunged the already impoverished country into years of deadly violence and one of the world's worst hunger crises.
At the start of the war, the Iran-backed rebel Houthi movement took control of most of northern Yemen, including the capital Sanaa, from the government. The conflict escalated in 2015, when a coalition of Arab states including Saudi Arabia and the UAE launched a military campaign to restore the government's rule.
A ceasefire has de-escalated the conflict with the Houthis in recent years and led to a freezing of the front lines.
The infighting escalated on 2 December, when the STC - which seeks an independent state in the south - launched a large-scale military offensive in the east of the country and rapidly took control of territory from government forces. The STC's advances included the oil-rich Hadramawt province that borders Saudi Arabia.
Tensions have further escalated with air strikes by the Saudi-led coalition, causing civilian casualties and destruction of military equipment thought to be tied to the UAE's support for the STC.
In a shocking turn, the UAE agreed to withdraw its forces from Yemen following Saudi demands, but analysts suggest that even without a physical presence, the STC's push for independence persists, signaling continued regional instability.
The consequences of this internal strife may lead to underserved suffering for millions as Yemen already grapples with one of the worst humanitarian crises in modern history.
