Southern separatists have vacated key public buildings in Yemen's port city of Aden that they had recently captured from forces loyal to President Abd-Rabbu Mansour Hadi, exposing divisions within the Saudi-Emirati coalition supporting the internationally-recognised government.
The supporters of the separatist Southern Transitional Council (STC) pulled out of the headquarters of Hadi's government, the supreme court and the central bank, as well as Aden's main hospital, more than a week after seizing them, Hadi's information minister Muammar al-Iryani said on Twitter on Saturday
"Measures are being completed to hand over the interior ministry and Aden refinery to presidential guard units under the supervision of the coalition," he tweeted.
The seizure of government military bases by separatist fighters a week ago has created a rift in the Saudi-Emirati military coalition formed four years ago to support Yemen's internationally-recognised government, based in Aden, against the Houthi rebels.
Forces of the separatist STC, trained and equipped by the United Arab Emirates, are a part of the anti-Houthi alliance, but the multi-layered war has rekindled old strains between north and south Yemen - formerly separate countries until 1990.
STC sources told Reuters news agency their forces, which had already moved away from the nearly empty presidential palace and central bank, were vacating government institutions under the supervision of a Saudi-UAE delegation.
But they said the forces would not quit the government military camps that give them effective control of the city.
"We will not retreat, we will not budge and planes will not scare us," a statement from one of the brigades fighting as part of the southern separatists said, as Saudi-led warplanes fired flares over Aden at dawn on Saturday.
"The STC and the southern forces do not answer, but to the demands of and the will of the people," Al-Khadher Sulaiman, director of the Office of Foreign Affairs of the STC in New York, told Al Jazeera.
"The legitimate government can ignore the popular will but the STC on the ground was compelled to act."
Southern calls for secession
On Thursday, thousands marched in Aden to express their support for the separatist fighters who seized the presidential palace from forces loyal to Yemen's internationally-recognised government, waving flags of the old state of South Yemen and chanting "Oh Revolution of the South".
Yemen was split into two countries during much of the Cold War before unifying in 1990.
Southern Yemen's population has long complained of marginalisation since its unification with the more populous north in 1990, with the STC seeking for the south's secession.
"The southern demands and the grievances and the aspirations of the people is to reinstate their pre-90s state of independence," said STC's Sulaiman. "These calls are not recent, they have been made for decades by the southern people.
The latest fighting, technically within the same military alliance, has killed at least 40 people and wounded 260 others, according to the United Nations, raising fears of a "civil war within a civil war".
After the UAE-backed separatists seized control of Aden, the Saudi-led coalition ordered an immediate ceasefire and threatened to bomb the separatists if they did not return to positions they held before the fighting.
It also called for the separatist movement and Hadi's government to attend talks in Saudi Arabia without offering a date.
The STC has since agreed to a Saudi-brokered ceasefire and welcomed Riyadh's call for dialogue.
A coalition statement overnight on Friday renewed a call for separatist forces to withdraw from all sites they have recently captured in Aden and urged to unite to fight the Houthis, who claimed drone attacks on oil installations at Shaybah in Saudi Arabia on Saturday.
The escalation in Aden has now made Yemen's civil war even more complex, as Saudi Arabia, along with the UAE, has been battling the Houthis in northern and western Yemen since March 2015.
The UAE in June scaled down its presence in Yemen, leaving behind thousands of southern forces it has built and trained.
Yemen's long-running war has triggered what the UN describes as the world's worst humanitarian crisis, with 24.1 million - more than two-thirds of the population - in need of aid.
Tens of thousands of people have been killed and millions forced from their homes.