UN Secretary-General Antonio Guterres on Friday called for a halt to violence in Yemen to pull the country back from a "precipice" and build momentum toward talks on ending the war.
The UN chief spoke hours after the Saudi-led coalition said it had attacked an airbase in the rebel-held capital of Sanaa and fighting flared between the Huthi rebels and pro-government forces near the key port of Hodeidah.
"First, violence must stop everywhere -- with an immediate halt around critical infrastructure and densely populated areas," Guterres told reporters at UN headquarters.
"Yemen today stands on a precipice," he said as UN aid agencies fear millions more could be pushed to the brink of famine in the conflict.
The Saudi-led coalition intervened in Yemen in 2015 to push back the Huthis and return President Abedrabbo Mansour Hadi to power.
The war has left nearly 10,000 people dead and unleashed what the United Nations describes as the world's worst humanitarian crisis.
Without action, up to 14 million people -- half of Yemen's population -- could be at risk in the coming months, up from 8 million who are now facing famine, said Guterres.
The UN appeal came just days after the United States, in a significant shift, piled pressure on its Saudi ally to end the war by calling for a ceasefire and peace talks.
"There is now an opportunity for peace in Yemen," Guterres said. "This building wave of momentum must be seized."
The United Nations is working to schedule talks between the government and the Huthis after a failed bid to hold a meeting in Geneva in September.
UN envoy Martin Griffiths, who recently met with US officials in Washington, is planning to invite the parties to talks in Sweden this month.
Britain is planning to present a draft Security Council resolution calling for the local ceasefires in cities and around infrastructure such as the port of Hodeida, diplomats said.
The Red Sea port is the entry point for more than 70 percent of imports to Yemen.
The UN chief called for opening up access to deliveries of food, fuel and others essentials, which the coalition has severely restricted, citing concerns that arms were being shipped to the Huthis under the cover of aid.
Yemen's economy must be propped up, by supporting the plummeting currency and ensuring that salaries and pensions are paid, he said.