The UN has accused Houthi fighters and their allies of blocking the delivery of desperately needed humanitarian supplies for 200,000 residents living in "virtual siege" in Yemen's third-largest city of Taiz.
The besieged city has become one of the major front lines in the fight for control of Yemen, with Houthi forces battling with fighters loyal to President Abd-Rabbu Mansour Hadi and Saudi-led coalition forces.
Aid agencies have warned of a major humanitarian disaster in the city for months, with reports of dire food and water shortages and hospitals struggling to function without access to fresh medical supplies.
The UN's Under-Secretary for Humanitarian Affairs and Emergency Relief Coordinator, Stephen O'Brien, said in a statement on Tuesday that "some 200,000 vulnerable civilians are living under a virtual state of siege".
"Al-Houthi and popular committees are blocking supply routes and continue to obstruct the delivery of urgently needed humanitarian aid and supplies into Taiz City," O'Brien said.
"Those hospitals that are still functioning are overwhelmed with wounded patients and face severe shortages of doctors and nurses, essential medicines and fuel.
"Despite repeated attempts by UN agencies and our humanitarian partners to negotiate access and reach people, our trucks have remained stuck at checkpoints and only very limited assistance has been allowed in."
O'Brien added that it was vital for all parties in the battle to "do their utmost to protect all civilians".
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His statement came as fighting continued on Wednesday, with sources telling Al Jazeera that 41 Houthi fighters had been killed in coalition air strikes and fighting with forces backing the president who recently returned to Yemen from exile in Saudi Arabia to help to oversee the offensive in Taiz.
The Saudi-led coalition launched the military campaign against the Houthis in March with the aim of restoring Hadi's government after the rebels captured the capital and large parts of the country.
At least 5,400 people have been killed, and at least 1.5 million people have been displaced since the war began.
Source: Al Jazeera