The U.N. special envoy for Yemen said Tuesday that every day a peace agreement is put off "needlessly extends the country's agony."
Ismail Ould Cheikh Ahmed spoke to the Security Council from Kuwait, where he has been mediating peace talks between Yemeni officials and the Houthi rebels who control large parts of the country.
Ahmed said he had given both sides a road map for a peace deal that included a Houthi withdrawal and disarmament and the formation of a unity government.
He said that while both sides had reacted positively to the road map, they had not been able to agree on a timetable, especially the key issue of when a new government would be formed.
An April truce in Yemen has generally held, despite what U.N. officials say have been serious violations, including the shelling of a market in Taiz on June 4, killing 18 civilians.
The Iranian-backed Houthi rebels seized the capital, Sana'a, in 2014, forcing the internationally-backed Yemeni government to temporarily flee to exile in Saudi Arabia.
Saudi-led airstrikes on the Houthis have compounded the misery in Yemen, where U.N. officials say 80 percent of civilians are in desperate need of food and medicine.