SANAA Militia forces loyal to Yemen's exiled government fought their way deep into the central city of Taiz on Sunday, local officials said, largely pushing out Houthi militiamen from the country's third largest city.
The tribal fighters seized a mountaintop citadel and an intelligence headquarters in battles with the Houthis and allied Yemeni army units, who control two military bases in the city.
Tank battles and air strikes have rocked Taiz since April, when the militia forces backed by Gulf Arab warplanes rose up against the Houthis. The combat has left much of the city in ruins and its residents pinned down inside their homes.
A civil war in Yemen erupted in late March when the Iran-allied Houthis, who had seized the capital Sanaa last September, drove southwards, forcing the government to flee into exile in Saudi Arabia and triggering a Gulf military intervention.
The Arab states say the Houthis are a proxy for Iran, an accusation the movement denies, countering that its advance a revolution against corrupt officials backed by the West.
More than 4,300 people have died in the conflict as hunger, disease and suffering have spread in the impoverished country.
Fighting had been stalemated for almost four months but the Houthis' opponents have gained the upper hand with training and weapons deliveries by the Gulf states, and have seized several southern provinces in an advance northward toward Sanaa.
Residents in the capital reported the first Gulf Arab air strikes on the city for about a month on Sunday targeting the main military airport and a weapons depot.
The United Nations' envoy to Yemen, Ismail Ould Cheikh Ahmed, has been shuttling between the warring sides, including the Houthis' representatives in neighbouring Oman, in an attempt to secure Houthi withdrawals from cities and spare Yemen's ancient capital from a devastating final battle.
"There is great progress in the ongoing negotiations in Muscat. The Houthis have agreed to the plan of the international envoy and the response of the Yemeni government is expected tomorrow," a Yemeni politician told Reuters on condition of anonymity.
(Reporting By Mohammed Ghobari; Writing by Noor Chehayber; Editing Noah Browning and Angus MacSwan)