A wounded Yemeni rebel awaits evacuation to the Omani capital Muscat from Sanaa on December 3, 2018

Stockholm (AFP) - A Yemeni rebel delegation arrived in Sweden Tuesday, accompanied by a UN peace envoy, for high-stakes talks with the government aimed at ending the country’s devastating war.

The Huthi rebels arrived on a Kuwaiti plane from Sanaa following a prisoner swap deal and the evacuation of 50 wounded insurgents for treatment in Oman in a major boost to peace efforts.

The United States hailed the announcement of peace talks in Sweden as a “necessary and vital first step” and called on all parties to “cease any ongoing hostilities.”

“We have no illusions that this process will be easy, but we welcome this necessary and vital first step,” said Heather Nauert, the State Department’s spokeswoman.

“Now is the time for Yemenis to replace conflict with reconciliation and work together to realize a brighter future for Yemen.”

The rebel delegation for the first peace talks since 2016 was accompanied by UN envoy Martin Griffiths. A government team, headed by Foreign Minister Khaled al-Yamani, was expected in Sweden Wednesday.

Although no date has been announced for the start of the negotiations, Yemeni government sources say they could begin on Thursday.

Mohammed Abdelsalam, heading the 12-member rebel deputation, tweeted the Huthis “will spare no effort to make a success of the talks to restore peace and end the aggression”.

At the same time, he called on rebel fighters to remain “vigilant against any attempt at a military escalation on the ground”.

UN spokesman Farhan Haq said preparations for the consultations were “ongoing”.

“We are confident that the two parties will meet this week in Sweden,” he told reporters at UN headquarters in New York.

An agreement to exchange hundreds of detainees was welcomed by the International Committee of the Red Cross, which will oversee the swap after the first round of planned peace talks in Sweden.

“This is one step in the right direction towards the building of mutual trust among Yemeni communities,” ICRC spokeswoman Mirella Hodeib said.

The deal was struck by Griffiths, in the rebel-held capital Sanaa for meetings already buoyed by the evacuation of wounded insurgents – a rebel precondition for talks.

A previous UN-brokered attempt to bring the Huthis and the Saudi-backed government to the negotiating table collapsed in Switzerland in September.

The United Arab Emirates (UAE), another key backer of the government, said the planned talks offered a “critical opportunity” to end nearly four years of war.

A wounded Yemeni rebel is transported by ambulance to Sanaa International Airport, before being evacuated to the Omani capital Muscat for treatment, on December 3, 2018

Yemeni government official Hadi Haig said between 1,500 and 2,000 members of pro-government forces and between 1,000 and 1,500 rebels would be released in the prisoner swap.

On the government side, they include former defence minister Mahmoud al-Subaihi, who has been held by rebels ever since they overran the capital in late 2014, and President Abedrabbo Mansour Hadi’s brother Nasser, a general and former senior intelligence official.

Rebel official Abdel Kader al-Murtadha confirmed the deal, adding he hoped it would be “implemented without problem”.

- Worst crisis ‘deteriorating’ -

Thousands of prisoners have been captured by both sides in the grinding war of attrition that has devastated Yemen at a cost of about 10,000 lives since the Saudi-led military intervention launched in March 2015.

The resulting humanitarian crisis, already the world’s worst, will deteriorate in 2019, the UN said Tuesday, warning the number of people needing food aid is set to jump by four million.

Yemeni mother Nadia Nahari holds her severely malnourished five-year-old son Abdelrahman Manhash, who weighs just five kilogrammes (11 pounds), at a treatment clinic in the government-held Khokha district of Hodeida province on November 22, 2018

Overall, 24 million people in Yemen – roughly 75 percent of the population – will need humanitarian assistance in 2019, UN humanitarian chief Mark Lowcock told reporters in Geneva.

If the negotiations in Sweden show results, “it is possible that we could find by the second half of the year that the extreme edge could get taken off the suffering of those people who have no form of income,” he said.

UN Yemen envoy Martin Griffiths arrives in the rebel-held capital Sanaa on November 21, 2018 as he intensifies his efforts to convene new peace talks in Sweden

International support for the new peace bid has been spurred by UN warnings that 14 million Yemenis are at risk of famine as the humanitarian situation deteriorates.

“This is not a country on the brink of catastrophe. This is a country that is in a catastrophe,” said World Food Programme chief David Beasley.

A coalition-backed government offensive on the rebel-held Red Sea port of Hodeida has threatened to cut virtually the only gateway for UN-supervised aid.

According to UN and Yemeni sources, the reopening of Sanaa international airport, which has been under coalition blockade, is among the confidence-building measures up for discussion in Sweden.

The coalition has largely suspended its offensive on Hodeida in the face of US-led calls for a ceasefire and new peace talks.

But fresh fighting flared on Monday and the coalition spokesman said military operations were “ongoing”.

Additional momentum towards peace has come from the mounting Western pressure on Saudi Arabia since the murder of dissident Saudi journalist Jamal Khashoggi inside the kingdom’s Istanbul consulate on October 2.