The humanitarian crisis in Yemen has worsened "dramatically" in the last week since UN-sponsored peace talks collapsed and fighting resumed in the port city of Hodeidah.
Lise Grande, UN humanitarian coordinator, said on Thursday that "hundreds of thousands of lives hang in the balance" in rebel-held Hodeidah, where "families are absolutely terrified by the bombardment, shelling and air strikes".
The three-year war has unleashed the world's most urgent humanitarian crisis in the nation of 28 million people with 22 million dependent on aid.
The UN warned ongoing fighting in Hodeidah, the entry point for the bulk of Yemen's commercial imports and aid supplies, could trigger famine in the impoverished nation where an estimated 8.4 million people are facing starvation.
"We're particularly worried about the Red Sea mill, which currently has 45,000 metric tonnes of food inside, enough to feed 3.5 million people for a month. If the mills are damaged or disrupted, the human cost will be incalculable," Grande said in a statement.
Battles rage
Yemeni forces, backed by a Saudi Arabia and United Arab Emirates-led coalition, seized the main road linking Hodeidah to the capital Sanaa, blocking a key supply route for the Houthi rebels in control of the country's north.
"The main entrance in Hodeidah leading to Sanaa has been closed after forces backed by the UAE took control of the road," a pro-coalition military source told the Reuters news agency.
Residents said the city's main eastern gate had been damaged in air raids and fighting was continuing on secondary streets off the main road.
There was no immediate word from either side of the conflict on their casualties.
Doctors and medics in two hospitals in Hodeidah province told the Associated Press news agency that 50 people have been killed in the past 24 hours.
Hundreds of civilians have fled their homes in Hodeidah to escape the fighting and heavy smoke was rising above parts of the city, AP quoted officials as saying.
The fighting in Hodeidah intensified following the collapse of UN-sponsored talks in Geneva last week after the Houthi delegation failed to show up.
'Living hell'
Coalition forces - which aim to restore the internationally recognised government of Abd-Rabbu Mansour Hadi, who fled Yemen after the Houthi takeover - believe their control over Hodeidah by cutting off supply lines would force the rebels to join the negotiating table.
However, Al Jazeera's Andrew Simmons, reporting from neighbouring Djibouti, said there were "warnings from all quarters that this offensive is the last thing needed in the run-up to an attempt to get some sort of dialogue going".
Martin Griffiths, the UN special envoy on Yemen, is expected to meet Houthi representatives as well as Yemeni government officials living in exile in Saudi Arabia this week in a bid to revive talks.
Meanwhile, Meritxell Relano, UNICEF's representative in Yemen, said more than 11 million children faced food shortages, disease, displacement, and lack of access to basic services.
"The conflict has made Yemen a living hell for its children," she said. "An estimated 1.8 million children are malnourished in the country. Nearly 400,000 of them are severely acute malnourished, and they are fighting for their lives every day."
According to the UN, at least 10,000 people have been killed since the Saudi-Emirati-led coalition intervened in Yemen in 2015. The death toll, however, has not been updated in years and is likely to be much higher.
