Severe fuel shortages forced the largest hospital in Yemen's southwestern province of Taiz to shut down on Sunday, affecting thousands of patients in the war-ravaged Arab country, a medical official said.

"All sections at Al-Thawra General Hospital, including a center specializing in treating kidney patients, have been shut down following a severe fuel crisis," the local medical official said on condition of anonymity.

"The hospital, the largest in Taiz, provides services for thousands of patients in the densely populated city," the official added, noting the shutdown has "put the patients' lives at risk."

The hospital has made urgent appeals to international organizations and UN agencies for providing fuel to help it overcome the crisis and avoid a health catastrophe, according to the official.

Yemen has been mired in a civil war since late 2014 when the Iran-backed Houthi militia stormed several northern cities and forced the Saudi-backed Yemeni government out of the capital Sanaa.

The war has killed tens of thousands of people, displaced 4 million, and pushed the country to the brink of starvation.