UN warns of 'dangerous escalatory cycle' in Yemen

Violent provocations by the rebels, who say they are showing solidarity with Palestinians in Gaza by attacking shipping, have prompted subsequent US and British air raids.

"I am engaging the Yemeni parties and relevant regional actors to support deescalation in the Red Sea to protect the mediation space in Yemen," Hans Grundberg told the Security Council.

"Three things need to happen in the immediate term to create an off-ramp to this dangerous escalatory cycle," Grundberg said.

He called for regional deescalation, for all parties to refrain from "military opportunism" and for progress towards a mediated agreement to be protected.

The Iran-backed Houthis have been fighting a Saudi-led coalition since 2015, months after they seized the capital Sanaa and most of Yemen's population centers, forcing the internationally recognised government south to Aden.

As recently as December, painstaking negotiations were gaining ground and the United Nations said the warring parties had agreed to work towards "the resumption of an inclusive political process".

The Houthi attacks in the Red Sea, as well as in the Gulf of Aden, in addition to Western retaliation, have thrown the peace process up in the air.

However, "in my latest exchanges, I have received assurances that all parties prefer the path to peace", Grundberg said.

Hundreds of thousands of people have died in the fighting and from indirect causes such as disease and malnutrition. More than 18 million Yemenis need "urgent support", according to the UN's humanitarian agency OCHA.

The Houthis' attacks have prompted some shipping companies to detour around southern Africa to avoid the Red Sea, a vital route that normally carries about 12 per cent of global maritime trade.

"Yemen is not a footnote to a wider regional story," Grundberg warned.

"The regional escalation does not negate the urgent needs in Yemen for a nationwide ceasefire."