Yemen's warring parties and beleaguered people cannot wait indefinitely for a roadmap to peace before the country slips back to war, the UN special envoy told AFP.
Hans Grundberg insisted it was "still possible" to solve the conflict in impoverished Yemen, where Iran-backed Huthi rebels control much of the country.
But any chance of implementing a roadmap has effectively been put on hold by escalating regional crises sparked by the war in Gaza.
Although preparatory discussions are continuing with all sides, "obviously... it cannot stay like this forever", Grundberg said in an interview at the Manama Dialogue conference in Bahrain.
"At a certain point, there is an expected delivery that the parties want to see happen. And if that doesn't take place, you risk losing the necessary momentum that you have, and that danger is clear."
He added: "There are belligerent voices in the region. What I'm saying is, don't go down that road -- it's possible to settle this conflict."
Yemen has been at war since March 2015, when a Saudi-led coalition began a campaign to dislodge the Huthis who had seized control of Yemen's capital, Sanaa, months earlier.
A UN-brokered ceasefire in April 2022 calmed fighting and in December last year, even after the Israel-Hamas war had started, the warring parties committed to a peace process.
But US and British strikes on Huthi targets in January, after the rebels began attacking shipping on the vital Red Sea trade route, "complicated the mediation space tremendously".
"On the basis of that, we have not been able to take the step forward from the commitments that were agreed to in 2023 to the assigned roadmap," Grundberg said.
The UN envoy said it's not "possible to move forward with the roadmap right now, because I don't think that the implementation of that roadmap would be possible".
But he added: "I still believe that the foundation for a roadmap in Yemen is there because the conflict between Yemenis is solvable.
"However, the complicating factor now is the regional destabilisation, where Yemen has become an integral part through the attacks in the Red Sea."
Grundberg said the roadmap is "not a magic wand" for Yemen, which has been plunged into one of the world's worst humanitarian crises with two-thirds of the population dependent on aid.
The Arabian Peninsula's poorest country is divided along regional, religious, political, tribal and factional lines, and has foreign influence at play including from Iran and the United Arab Emirates.
The roadmap is intended as a structure for implementing humanitarian and economic commitments, and steps towards a permanent ceasefire and political process, over a nominal period of three years.
"So here I think the responsibility that lies on our side is to ensure that this momentum is upheld and that the parties understand the necessity to... trust in the fact that this is possible to achieve," Grundberg said.
"If not, the consequences are known. If you slip back into a violent confrontation internally, I think the consequences of that are pretty well known and I don't think that they would be in favour of anyone."
He added: "I would guess that the Yemeni people should be impatient as a whole. I think that they have been waiting for peace for far too long.
"Everyone wants this to come to an end."
