The Security Council has postponed a vote on a draft resolution demanding a 30-day ceasefire across Syria, till 12 p.m. EST (1700 GMT) on Saturday, said Kuwaiti ambassador to the United Nations Mansour Al-Otaibi.
Al-Otaibi, who is president of the Security Council for the month of February, said the council members failed to reach consensus on Friday after rounds of closed-door consultations.
He said the council members were "very close" to consensus but failed to close all the gaps.
"We are working to have a consensual draft resolution and hopefully the council will be united and all of them -- the 15 -- will vote in favor," he told reporters.
The resolution, drafted by Kuwait and Sweden, demands a 30-day ceasefire across Syria so that humanitarian aid can be through and those critically ill can be evacuated from besieged areas. A vote on the text was originally scheduled for 11 a.m. EST (1600 GMT) Friday.
Swedish UN ambassador Olof Skoog said he was "extremely frustrated" by the impasse on Friday.
"I am extremely frustrated with the fact that the Security Council has not been able to adopt the resolution to try to alleviate the suffering of the Syrian people."
He said the text will be voted on Saturday one way or the other. "We are not going to give up because the situation on the ground calls for a Security Council resolution that demands a cease-fire," said Skoog, referring to the recent escalation of violence.
"I hope we will adopt something forceful, meaningful and impactful tomorrow," he told reporters.
Skoog said the council members were "very very close" to consensus on Friday but they were not able to close the gap completely.
He indicated that the main difference was over the timetable for ceasefire. "I think we all agree that there needs to be a ceasefire that has to be urgent immediately. There are still some discussions on exactly how to define that."
An earlier text provides for the start of cease-fire 72 hours after the adoption of the resolution.
In response to calls by the UN Humanitarian Coordinator and other UN representatives in Syria for a cessation of hostilities of at least one month to improve the humanitarian situation, Kuwait and Sweden circulated a draft resolution on Feb. 9. However, consultations dragged on for two weeks without consensus. Russia, which has veto power as a permanent member of the Security Council, demanded amendments.