Separatists in southern Yemen have taken effective control of Aden, the internationally recognized seat of government, weakening the Saudi-led coalition that is trying to end the Iran-aligned Houthi movement in the country.
In a move that complicates United Nations efforts to end a four-year war, 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 presidential palace, but it was empty.
"What is happening in the temporary (government) capital of Aden by the Southern Transition Council is a blow to internationally recognized government institutions," the Foreign Ministry said in a Twitter post.
Although they have a rival agenda for President Abd-Rabbu Mansour Hadi's government about the future of Yemen, the separatists are part of the Saudi ruling coalition that has been fighting the Houthis since March of 2015.
The war has already killed tens of thousands of people and has driven the poorest country in the Arabian Peninsula to the brink of famine.
Four days of clashes between separatists and government forces killed at least nine civilians and more than 20 fighters, medical sources said. The fighting, which has trapped civilians in their homes with shrinking water supplies, resumed early on Saturday, but has since waned.
"It's all over, the Southern Transition Council forces are in control of all military camps," a Hadi government official told Reuters.
The separatist commander, speaking in a video message circulated by supporters of the movement, said his forces had not met resistance at the palace, located in the predominantly residential district of Crater. A witness told Reuters the separatists were now inside the palace.
The separatists also took over the home 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 were no immediate comments from the West-led Sunni coalition, led by Saudi Arabia, which intervened after the Houthis overthrew Hadi's government from power in the capital Sanaa at the end of 2014.
The United Arab Emirates Alliance member, who armed and trained thousands of southern separatist fighters, previously called for calm and a renewed focus on opposing the Houthis.
Foreign Minister Sheikh Abdullah Bin Zayed has called on UN Special Envoy Martin Griffiths, who is trying to ease tensions in Yemen, "to mobilize efforts and exert pressure" to this end.
Clashes between government and separatist forces began on Wednesday after it accused an Islamic party allied with Hadi of complicity in a missile strike against a military parade of southern forces in Aden, which was claimed by the Houthis.
Analysts say the Houthis may have used the attack to test ground dynamics after the United Arab Emirates reduced their presence under pressure from Western allies to end the war and concerns over growing tensions with Iran in the Gulf.
Separatists moving against Hadi could weaken the coalition's hand in any negotiations with the Houthis to form a transitional government to end the war.
"This is good news for the Houthis and bad news for the Saudis ... it ends with the exclusivity of the Houthis as the coup against Hadi," Chatham House associate member Farea al-Muslimi told Reuters.
Houthi's deputy foreign minister said on Saturday events in Aden proved that the Hadi government, which owns Aden and a number of western coastal cities, was not in a position to rule.
"It's time for the major local powers to hold serious and constructive talks to bring Yemen to a federation that appeasates all sides under a united national framework," tweeted Hussein al-Azzi.
The UN is trying to implement a peace deal in the main port city of Hodeidah, to the north, to pave the way for broader political negotiations to end the war.
The Houthis, which control Sanaa, Hodeidah and other urban centers, have intensified missile and drone attacks on Saudi cities, complicating UN efforts to implement the Hodeida troop withdrawal agreement between the Houthis and the Hadi government in Sweden. December.
Yemen's conflict is widely seen in the region as a war between Saudi Arabia and Iran. The Houthis say their revolution is against corruption.