Talks to ease the violence in Yemen have been stalled for months, with the conflict escalating since March when a pro-government coalition led by Saudi Arabia began bombarding Iran-backed Huthi rebels.
With the humanitarian crisis in the impoverished country deteriorating, UN envoy Ismail Ould Cheikh Ahmed said a swift halt to the fighting was
imperative for those caught up in what has increasingly become a regional conflict.
Ahmed told reporters that three delegations would take part in talks, likely to be held outside Geneva, which have no definitive timeline and will last "as long as it takes."
The delegations include representatives of President Abedrabbo Mansour Hadi's government, the Huthi rebels, and officials from the General People's Congress (GPC), who are loyalists of former president Ali Abdullah Saleh.
Though not formally aligned, some GPC members have expressed support for the Huthis.
The UN envoy further said he was "almost certain" a temporary ceasefire would be in force by December 15 "in order to create an environment conducive to peace talks."
"Everyone seems to be welcoming this idea that we will have a ceasefire," Ahmed said, noting that a permanent ceasefire remained a more distant prospect and would depend on the outcome of negotiations.
According to the UN envoy, Riyadh said it would observe a ceasefire and pause its aerial assault so long as Hadi was on board with the plan.
Each delegation will be made up of 12 members, including eight official negotiators and four advisors.
The delegations have not yet been finalized, in part because the UN has insisted that more women be included, according to Ahmed.