United Nations Yemen envoy Martin Griffiths said on Thursday he expects the warring parties to formally adopt "in the immediate future" agreements on a nationwide ceasefire, key economic and humanitarian measures and a resumption of political talks.

Yemen has been mired in conflict since the Iran-aligned Houthi group ousted the government of President Abd Rabbu Mansour Hadi from the capital Sanaa in late 2014. A Saudi-led military coalition in 2015 intervened in a bid to restore the government.

Griffiths told the U.N. Security Council he has been negotiating with the parties on the texts of his proposals for the past two weeks. "We expect them to agree on and formally adopt these agreements in the immediate future," he said.

He said the economic and humanitarian measures could include: release of prisoners and detainees, opening Sanaa airport, paying civil servant salaries, opening access roads, and ensuring entry at Hudeidah ports for ships carrying commodities that will help in the fight against COVID-19, the potentially lethal respiratory disease caused by the coronavirus.

"The conversations we had with the two parties, and our consultations with the Saudi-led Coalition among other international actors ... are continuous, detailed and constructive," Griffith said.

He said "good progress" was being made and the United Nations was redoubling its efforts to bridge outstanding differences "before we convene them at a meeting where ... these agreements will be tabled, confirmed - I hope."

Griffith's latest push for peace for Yemen was sparked by U.N. Secretary-General Antonio Guterres's call last month for a global ceasefire so the world can focus on fighting the coronavirus pandemic. 

So far only one case of COVID-19 has been confirmed in Yemen, where around 80% of the population, or 24 million people, require humanitarian aid.

But aid groups fear that could be a harbinger of a catastrophic outbreak given Yemen's shattered health system and widespread hunger and disease after five years of war in which more than 100,000 have been killed.

"Epidemiologists warn that COVID-19 in Yemen could spread faster, more widely and with deadlier consequences than in many other countries," U.N. aid chief Mark Lowcock told the Security Council on Thursday.

He also warned that the world's largest aid operation needed money and that three-quarters of the United Nations 41 major programs "will start closing down in the next few weeks if we can't secure additional funds."

"This means we will have to start eliminating many of the activities that may offer Yemenis' the best chance to avoid COVID-19," Lowcock said.