The UN insisted Tuesday that aid must immediately be allowed to enter Yemen's Taiz, besieged by pro-Iran Houthi fighters who are preventing supplies from reaching the country's third-largest city.
Houthi fighters have encircled Taiz since early October, blocking the road that links it to Aden, interim capital of the Saudi-backed, internationally-recognised government.
"Humanitarian aid must be immediately allowed to enter the city and its passage must be facilitated," UN human rights chief Volker Turk said in a statement.
He said relief must reach the city to avert a rights catastrophe.
"The Houthis' closure of the only supply route linking Taiz to Aden is placing civilians at grave risk, blocking humanitarian aid and cutting off essential supplies," said Turk.
The Houthis, from Yemen's rugged north, seized the capital Sanaa in 2014, sparking a brutal civil war with a Saudi-led coalition fighting for the government.
The civil war reignited in July, months into the US-Iran conflict that has plunged the Middle East into crisis.
Turk said the encirclement of Taiz had sent the prices of commodities soaring, leaving many without food or other basic necessities.
His office has also noted restrictions on safe access to water and essential goods, exacerbating humanitarian needs and increasing risks for civilians.
"Civilians wishing to leave must be allowed to do so freely and safely," said Turk, the UN high commissioner for human rights.
Turk's office said it had verified that 32 civilians had been killed across Taiz governorate between August 1 and October 19, including nine women and 14 children.
Meanwhile 115 civilians were injured, among them 34 women and 36 children.
Turk warned that with fighting moving closer to densely populated areas of the city, the risk of death and injury to civilians would only increase.
"I urge all parties to the conflict to refrain from the use of explosive weapons with wide-area effects in populated areas and to take all feasible precautions to protect civilians and civilian objects," he said.
The World Health Organisation said that Taiz's health system was now at "critical risk".
"Fighting and road closures are threatening hospitals' access to fuel, oxygen, medicines and essential supplies, putting patients requiring life-saving care at immediate risk," WHO spokesman Tarik Jasarevic told a press conference.
The UN health agency is calling for the safe movement of patients, health workers, ambulances, fuel, oxygen and medicines to the city.
Jasarevic said 12 hospitals in Taiz had around four days of fuel left, while there are stocks of one week or less for 115 out of 127 essential medicines.
He said the health crisis across Yemen was escalating rapidly, with rising disease outbreaks placing "immense pressure on an already overstretched health system".
Across Yemen, suspected cholera cases have tripled from 221 in the week ending September 12 to 683 in the week ending October 10.
Yemen has reported this year more than 22,800 suspected measles cases and 128 deaths, alongside 12,618 suspected dengue cases and 421 suspected diphtheria cases.
