Yemen's southern separatists have taken effective control of Aden, seat of the internationally recognised government, fracturing the Saudi-led coalition which is trying to break the grip of the Iran-aligned Houthi movement on the country.
In a move that complicates efforts by the United Nations to end a four-year war, the separatists seized control of all government military camps in the southern port city on Saturday, officials said. A separatist military commander later said they had also taken the all-but empty presidential palace.
"What is happening in the temporary (government) capital of Aden by the Southern Transitional Council is a coup against institutions of the internationally recognised government," the foreign ministry said in a Twitter post.
Although they have a rival agenda to President Abd-Rabbu Mansour Hadi's government on the future of Yemen, the separatists have been part of the Saudi-led pro-government coalition that has been battling the Houthis since March 2015.
The war has killed tens of thousands and pushed the poorest Arabian Peninsula nation to the brink of famine.
Four days of clashes between the separatists and government forces have killed at least nine civilians and more than 20 combatants, according to medical sources. The fighting, which trapped civilians in their homes with dwindling water supplies, resumed at dawn on Saturday but has since abated.
"It is all over, the (Southern Transitional Council) forces are in control of all the military camps," an official in Hadi's government told Reuters.
The separatist commander, speaking in a video message circulated by the movement's supporters, said their forces had not encountered resistance at the palace, located in the predominantly residential Crater district. A witness told Reuters the separatists were now inside the palace.
The separatists also took over the house of Interior Minister Ahmed al-Mayssari after he was evacuated by coalition forces, government officials said. President Hadi is based in the Saudi capital Riyadh.
There was no immediate comment from the Western-backed, Sunni Muslim coalition led by Saudi Arabia that intervened after the Houthis ousted Hadi's government from power in the capital Sanaa in late 2014.
Alliance member the United Arab Emirates, which has armed and trained thousands of southern separatist fighters, earlier called for calm and a renewed focus on opposing the Houthis.
Foreign Minister Sheikh Abdullah Bin Zayed urged UN special envoy Martin Griffiths, who is trying to de-escalate tensions across Yemen, "to deploy efforts and exert pressure" to that purpose.
Coalition's hand weakened
The clashes between government forces and separatists began on Wednesday after the latter accused an Islamist party allied to Hadi of complicity in a missile attack on a southern forces military parade in Aden, which was claimed by the Houthis.
Analysts say the Houthis may have used the attack to test dynamics on the ground after the UAE in June scaled down its presence under pressure from Western allies to end the war and concerns about rising tensions with Iran in the Gulf.
The separatists move against Hadi could weaken the coalition's hand in any negotiations with the Houthis to form a transitional government to end the war.
"It's good news for the Houthis and really bad news for the Saudis ... It ends the exclusivity of the Houthis being the coup against Hadi," Farea al-Muslimi, an associate fellow at Chatham House, told Reuters.
The Houthi's deputy foreign minister said on Saturday that the events in Aden proved Hadi's government, which holds Aden and a string of western coastal towns, was not fit to rule.
"It is time for the main powers on the ground to hold serious and constructive talks to take Yemen towards a federation that appeases all sides under a united national framework," Hussein al-Azzi tweeted.
The UN is trying to implement a stalled peace deal in the main port city of Hodeidah, further to the north, to pave the way for wider political negotiations to end the war.
The Houthis, who control Sanaa, Hodeidah and other urban centres, have stepped up missile and drone attacks on Saudi cities, complicating the UN's efforts to implement the troop withdrawal deal in Hodeidah that was reached between the Houthis and Hadi's government in Sweden in December.
The Yemen conflict is widely seen in the region as a proxy war between Saudi Arabia and Iran. The Houthis say their revolution is against corruption.
In a move that complicates efforts by the United Nations to end a four-year war, the separatists seized control of all government military camps in the southern port city on Saturday, officials said.