The rebel alliance controlling Yemen's capital appeared to crumble Saturday as a strongman opposed to the internationally recognised government reached out to a Saudi-led coalition fighting the insurgents.
The rift within rebel ranks erupted into violence in Sanaa this week, raising fears of a new front in a three-year war that has claimed thousands of lives and triggered a humanitarian catastrophe.
Ex-president Ali Abdullah Saleh, who joined forces with the Iran-backed Huthi rebels to seize the capital in 2014, said he was ready to talk to the Saudi-led coalition if it lifts a crippling blockade on Yemen.
His about-face sparked warnings of retribution by the Huthis, whose leader accused Saleh of "great treason".
Dozens of fighters on both sides were killed in the clashes this week. Rebel chief Abdul Malik al-Huthi confirmed at least 40 killed or injured. Security sources in Sanaa put the toll at more than 60.
The armed groups fought Saturday for key positions in the city, including ministries and the international airport, security sources and witnesses said.
Sanaa international airport is under a crippling blockade the coalition imposed last month after a Huthi missile was intercepted near Riyadh.
Sanaa streets were empty Saturday night as Yemenis stayed home, fearing renewed clashes. One resident described the city as a "ghost town".
- Rebels denounce 'coup' -
For decades bitter enemies, Saleh and rebel chief Abdulmalik al-Huthi joined forces three years ago to drive President Abedrabbo Mansour Hadi's government from Sanaa.
But their fragile alliance has shown signs of unravelling for months.
Saleh's open overture to Riyadh came a day after talks with the Huthis failed to broker a truce.
"I call on our brothers in neighbouring countries... to stop their aggression and lift the blockade... and we will turn the page," he said in a televised speech.
"We vow to our brothers and neighbours that, after a ceasefire is in place and the blockade is lifted ... we will hold dialogue directly through the legitimate authority represented by our parliament."
The Huthi chief said Saleh and the Saudi-led coalition had become "one front" after the former president's "great treason".
The Huthis' political office accused Saleh of staging a "coup" against "an alliance he never believed in", and warned that Saudi Arabia and its allies would "pay a heavy price in their own capitals".
- 'Iran-backed militias' -
Yemen's war has claimed more than 8,750 lives since the Saudi-led coalition intervened to prop up Hadi's government against the rebels in 2015, triggering what the United Nations has described as the world's worst humanitarian crisis.
UN envoy Ismail Ould Cheikh Ahmed said he was "deeply concerned", urging all sides to "exercise restraint" and avoid targeting civilians.
The UN also implored the coalition to fully open up Red Sea ports to allow aid deliveries, warning that "more than eight million people could starve without urgent food assistance coming into Yemen".
The coalition welcomed Saleh's offer of talks.
"The decision by (Saleh's) General People's Congress to take the lead and their choice to side with their people will free Yemen of... militias loyal to Iran," it said in a statement carried by the official Saudi Press Agency.
Hadi's government also appeared to welcome Saleh's move away from the Huthis, whom it accuses of promoting Iranian interests in Yemen.
"We declare our determination to... preserve the Arab identity of Yemen and the unity of its territory and cooperate with every loyal Yemeni citizen working to rid our country of these vicious gangs," it said in a statement.
Saudi Arabia and the United States have accused Iran of supplying weapons to the Huthis, which Tehran strongly denies.
A minister from the UAE, a key member of the military coalition, on Saturday praised what he called the "Sanaa uprising".
Anwar Gargash, state minister for foreign affairs, tweeted his support for "the Yemeni people's return to their Arab environment", echoing to the coalition accusations that the Huthis are loyal to Iran.
Saleh ruled Yemen as president for 33 years after the 1990 unification of north and south Yemen.
A longtime ally of Saudi Arabia, he waged six separate wars against the Huthis, Zaidi Shiites who hail from northern Yemen.
Saleh resigned under popular and political pressure in 2012, ceding power to his then-vice president Hadi, who now lives in exile in Saudi Arabia.
In 2014, Saleh announced he had joined forces with the Huthis, seizing the capital and setting up a parallel government as Hadi's administration fled to Aden.