The UN on Thursday called for an end to the Iran-backed Houthi rebels' intensifying offensive on Marib in northern Yemen and warned that its eventual fall could lead to the displacement of 450,000 people.
UN spokesman Stephane Dujarric said 35,000 people had been displaced by the Houthi advance on Marib city since September and that human suffering would increase with further rebel gains.
“We're also deeply concerned that the conditions could quickly get worse if fighting enters the city,” Mr Dujarric said.
“Aid agencies estimate it could displace another 450,000 people. The UN continues to call for an immediate end to the Marib offensive and a nationwide ceasefire.”
About two million people who were displaced by earlier battles in Yemen's conflict fled to Marib, according to a recent Red Cross estimate, and its fall could lead to hundreds of thousands of them being forced to move again.
The assault on Marib began in February and has intensified in recent weeks, with Houthi gains across the gas and oil-producing region and increased air strikes by the Saudi Arabia-led coalition to deter them.
The Saudi-led coalition intervened in 2015 to restore the internationally recognised Yemeni government that was overthrown when the Houthis seized the capital Sanaa the previous year.
UN special envoy Hans Grundberg on Thursday ended a three-day tour of Yemen and briefed a closed-door meeting of the UN Security Council in New York by video conference in an effort to revive the stalled peace process.
Mr Grundberg lamented the hardships ordinary Yemenis “face moving through their daily lives” after seven years of war, and called for a “sustainable solution to the conflict”.
The coalition announced on Thursday a new death toll of 125 Houthi fighters from its latest barrage of 22 strikes around Marib in the previous 24 hours, Saudi state media reported.
The coalition said the operations took place in Sirwah to the east of Marib city and Al Bayda province to the south, and also destroyed 14 military vehicles.
Hassan Nasrallah, head of the Lebanese militia Hezbollah, said on Thursday that the fall of Marib would have “very big” consequences for Yemen and called the war a "resounding failure".
The Security Council this week imposed sanctions on Houthi chief of general staff Muhammad Abd Al-Karim Al-Ghamari and two other rebel leaders linked to cross-border attacks from Yemen into Saudi Arabia, and to fighting in Marib.
“The continuing cross-border attacks by the Houthis are unacceptable,” Britain’s UN ambassador James Kariuki said on Thursday.