Sanaa: Fresh gun battles forced shops and schools to close in Yemen's capital Sanaa on Sunday as residents warned a three-year rebel alliance was collapsing into a "street war".
The Iran-backed Houthi rebels' partnership with ex-president Ali Abdullah Saleh appeared to have fallen apart after he reached out to a military coalition fighting the insurgents.
The Houthis' political office on Saturday accused Saleh of staging a "coup" against "an alliance he never believed in".
On Sunday, Saleh loyalists cut off a number of streets in central Sanaa and deployed heavily in anticipation of Houthi attacks, as security sources said clashes had already left some 60 dead across the capital and at its international airport.
Saleh loyalists renewed a bid to seize control of Al Jarraf district, a stronghold of the Houthis, while the Houthis fortified their positions with dozens of vehicles mounted with machine guns, witnesses said.
Sanaa residents said they had barricaded themselves in their homes to avoid snipers and shelling as clashes flared up around key ministries where the two sides had been working together just days before.
The education ministry cancelled classes on Sunday, normally the start of the school week, and witnesses said some bodies of those killed in previous clashes were still lying in the streets.
Iyad Al Othmani, 33, said he had not left his house for three days because of the clashes.
Mohammed Abdullah, a private sector employee, said his street had been cut off by militiamen and he was staying home to avoid checkpoints.
"Sanaa is becoming like a ghost town. There is a street war and people are holed up in their houses," according to an activist who works with the International Organisation for Migration in Sanaa.
"If the confrontation continues, many families will be cut off" and stranded in their homes, he warned.
Three years after they joined forces to drive the government of President Abedrabbo Mansour Hadi from Sanaa, the collapse of the Houthi-Saleh alliance is a key shift in Yemen's complex war.
Saleh ruled Yemen as president for 33 years after the 1990 unification of north and south Yemen.
He waged six separate wars against the Houthis, Zaidi Shi'ites 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 Iran-backed Houthis, seizing the capital and setting up a parallel government as Hadi's administration fled to Aden.
That triggered an Arab force to intervene to prop up Hadi's government, an escalation in a war that has since killed more than 8,750 people and dragged the country towards what the United Nations calls the world's worst humanitarian crisis.
On Saturday, Saleh reached out to the Saudi-led coalition, offering to "turn the page" if it lifts a crippling blockade on the country.
The Houthis accused him of staging a "coup against our alliance".
The military coalition carried out dawn air raids against Houthi positions in the hills south of Sanaa on Sunday, but it was not clear if the strikes were meant to benefit Saleh's forces.
A coalition spokesman could not immediately be reached for comment.