A Saudi-led coalition launched Sunday a strike against southern separatists in Yemen after they seized the presidential palace in second city Aden in deadly fighting that threatened to deepen the country's humanitarian crisis.
The seizure, decried by the Riyadh-backed Yemeni government as a UAE-supported coup, reflects deep divisions between secessionists and loyalist forces, both of whom have fought Shiite Huthi rebels.
"The coalition targeted an area that poses a direct threat to one of the important sites of the legitimate government," a coalition statement said, calling on the separatist Southern Transitional Council (STC) to withdraw from positions seized in Aden or face further attacks.
It did not specify the target but residents in Aden told AFP it was an air strike against separatist camps in the city.
Riyadh-based Yemeni President Abedrabbo Mansour Hadi is backed by the coalition - led by Saudi Arabia and its ally the United Arab Emirates - that is battling the Iran-aligned Huthis.
But another force in the anti-Huthi coalition - the UAE-trained Security Belt Force - has since Wednesday been battling loyalists in Aden, the temporary base of Hadi's government.
The Security Belt Force is dominated by fighters who back the STC, which seeks to restore south Yemen as an independent state as it was from 1967-90.
The International Crisis Group think tank warned that the Aden clashes "threaten to tip southern Yemen into a civil war within a civil war."
"Such a conflict would deepen what is already the world's worst humanitarian crisis," it said.
The coalition called for an "immediate cease-fire" and the Saudi foreign ministry has demanded an "urgent meeting" between the warring parties.
Both the Yemeni government and separatists said early Sunday they backed Riyadh's call for dialogue and a suspension of fighting.
But in a sermon to mark the start of the Muslim Eid al-Adha festival, STC vice president Hani bin Breik said his group will not "negotiate under threat."
Saudi Deputy Defence Minister Khalid bin Salman also called for an "immediate cessation of hostilities and withdrawal from all forcefully occupied locations in Aden."
