UN Secretary General Ban Ki-moon has said that there is little evidence that Syria's government is complying with a peace plan to try to end violence.
After briefing the Security Council, he warned there was an "imminent" danger of civil war in Syria and it could go from tipping point to breaking point.
Meanwhile, UN envoy Kofi Annan said the council should put more pressure on Damascus to implement his peace plan.
The comments come after reports that 78 people were killed in central Syria.
Opposition activists blame the killings on pro-government forces but the government accuses "terrorists".
UN monitors were trying to reach the village just hours later were fired upon, but none were hurt in the shooting.