UN special envoy Ismail Ould Cheikh Ahmed told AFP that negotiations were underway to stave off a feared military attack on the vital Red Sea port of Hodeida, in what he hoped would be a first step towards a ceasefire.
Averting an attack on Hodeida - the main entry point for desperately needed aid to Yemen - could allow "a real cessation of hostilities and to go back to the talks," he said.
The Muslim holy fasting month of Ramadan is set to begin around May 27 this year.
Even if Ould Cheikh Ahmed manages to get the parties to the table, any success will be hard-won: since Yemen's conflict escalated two years ago, all UN mediation attempts and seven declared ceasefires have failed.
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Yemen's war has pitted pro-government forces against Iran-backed Huthi rebels and their allies, renegade troops loyal to former president Ali Abdullah Saleh.
More than 7,700 people have been killed in the past two years of fighting, while the country has plunged into a deep humanitarian crisis and faces the imminent risk of famine.
Hodeida is currently controlled by the Huthis, but fears are mounting over a potential coalition offensive.
The UN and other organisations have urged the Saudi-led coalition not to bomb Hodeida, Yemen's fourth most populated city, and a "major lifeline for a country on the verge of starvation".
At the same time, he said, he was hearing concerns from the coalition that the port was being used to smuggle in weapons.
"We are trying to explore various options by which we can reinforce inspection mechanisms maybe or see how we can minimise the risk of any additional smuggling," he said.
The UN mediator said the Huthis had voiced interest in his proposals and that he aimed to invite them to a meeting in Oman next month to discuss different options.