At least 35 fighters have been killed in Yemen in clashes between Shiite rebels and pro-government forces in Taiz, the country's third-largest city, according to officials.

The officials said Shiite rebels were trying to retake the western part of the city, while a Saudi-led coalition launched more than a dozen air strikes to prevent the Houthis from advancing.

Yemen's civil war pits Houthi rebels against fighters allied with the internationally recognised government. A Saudi-led coalition began air strikes against the Houthis in March last year.

The Houthis had besieged Taiz for over a year until pro-government forces pushed them out of the western part of the city last week, reopening a passage into Taiz.