Yemen's southern separatist movement has announced a constitution and aims to hold a referendum on independence from the north.

It is not immediately clear if the move by the Southern Transitional Council (STC), backed by the United Arab Emirates (UAE), could be implemented or was largely symbolic.

But it is an escalation of a confrontation that has pitted Saudi Arabia, which supports Yemen's internationally recognised government, and the UAE against each other.

The UAE announced it was pulling its troops out of Yemen shortly after the separatists' statement.

Last month, STC-linked fighters seized control of two southern provinces from Saudi-backed forces and took over the presidential palace in the south's main city, Aden, forcing the government there to flee to the Saudi capital, Riyadh.

On Friday, Saudi warplanes bombed camps and military positions held by the STC in Hadramout province as Saudi-backed fighters tried to seize the facilities, a separatist official said.

Image: Footage reportedly shows Saudi airstrikes targeting STC positions in Sayoun, Hadramout province, on Friday. Pic: Reuters

It was the latest intervention by Saudi Arabia, which in recent weeks has bombed STC forces and struck what it said was a shipment of Emirati weapons destined for the separatists.

Saudi Arabia, the UAE, and their allies in Yemen have all been part of a Saudi-led coalition fighting Iranian-backed Houthi rebels who control the north. The decade-long civil war has devastated the Arab world's poorest country.

In December, Saudi Arabia targeted Yemen port over 'weapons shipment'

The coalition's goal is to restore the internationally recognised government, which was driven out of the north by the Houthis. But tensions between the factions and the two Gulf nations appear to be unravelling the coalition.

'The right to self-determination'

The head of the STC, Aidarous al Zoubeidi, issued a video statement on Friday saying the constitution would be in effect for two years, after which a referendum would be held on "exercising the right to self-determination for the people of the South".

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During those two years, he said, the "relevant parties" in north and south Yemen should hold a dialogue on "a path and mechanisms that guarantee the right of the people of the South".

The 30-article constitution describes the creation of "the State of South Arabia", covering the same territory as the former People's Democratic Republic of Yemen, the independent southern state that existed from 1967 to 1990.

Image: Soldiers loyal to the STC, which wants an independent southern state, at a checkpoint in Aden on Wednesday. Pic: AP

It was not clear what practical impact it would have. But the declaration could set back efforts to avert an outright conflict between the separatists and the rest of the Saudi-led coalition.

The UAE's foreign ministry said in a statement that the country was dealing with the situation "with restraint, coordination, and a deliberate commitment to de-escalation, guided by a foreign policy that consistently prioritises regional stability over impulsive action".

In a post on X, the Saudi ambassador to Yemen, Mohammed al-Jaber, said the kingdom had tried "all efforts with STC" for weeks "to stop the escalation" and urge the separatists to leave Hadramout and Mahra, but faced "continued intransigence and rejection from Aidarous al Zoubeidi".