Peace talks aimed at ending nearly four years of civil war in Yemen, described by the UN special envoy as an important milestone, have started in Sweden.
Martin Griffiths announced the signing of a prisoner swap deal that would see thousands of families reunited.
His team is working alongside delegations from the Yemeni government and the Houthi rebels to enable informal talks due to last a week.
The war has caused the world’s worst humanitarian crisis in recent times.
Thousands of people have died in fighting and millions have been pushed to the brink of starvation.
Consultations are resuming for the first time since 2016. The last attempt at a negotiated peace collapsed in September when the Houthis failed to show up for talks in Geneva.
The latest talks are not expected to deliver a breakthrough. Correspondents say the key aim of this round is to prevent an all-out battle for the rebel-held Red Sea port of Hudaydah where thousands of civilians are trapped.
The UN also hopes to come up with a framework for talks on what a future political solution in Yemen will look like.
“During the coming days we will have a critical opportunity to give momentum to the peace process,” Mr Griffiths told reporters as talks began at a renovated castle in Stockholm on Thursday.
The UN envoy also confirmed that an agreement had been signed by both sides allowing for the exchange of prisoners, designed as a confidence-building measure.
He did not specify numbers but said that thousands of families would benefit from the move.