Syria envoy Kofi Annan and UN Secretary General Ban Ki-moon briefed the United Nations Security Council on the escalating conflict, at a closed-door meeting in New York late on Thursday.

Joint UN and Arab League envoy Annan said that although fighters on the ground were not honoring the terms of his six-point peace plan, he still hoped it could succeed.

"If things do not change, the future is likely to be one of brutal repression, massacres, sectarian violence, and even all-out civil war," Annan told the council, saying that "all Syrians will lose" in such a situation.

The former UN secretary general said that "individual actions or interventions will not resolve the crisis," urging the council to agree on unanimous measures to stop the bloodshed.

"If we genuinely unite behind one process and act and speak with one voice, I believe it is still possible to avert the worst and enable Syria to emerge from this crisis," Annan said.

The Ghanaian diplomat spoke to reporters after the Security Council session, along with UN Secretary General Ban Ki-moon and Arab League Secretary General Nabil el-Araby.

"The three of us agree," Ban said, "Syria can quickly go from a tipping point to a breaking point. The danger of full-scale civil war is imminent and real, with catastrophic consequences for Syria and the region."

Monitors unable to reach Qubair

The Security Council convened a day after reports of a "massacre" in the town of Qubair, in the central region of Hama. Opposition activists said government forces and militia loyal to Assad killed some 78 people, while the government in Damascus said the killings were perpetrated by terrorists.

UN monitors, present in Syria as part of Annan's peace plan, sought to visit the site on Thursday, but Ban said that they were "shot at with small arms" and were turned away by the Syrian army.

Kofi Annan also told reporters that talks were continuing on the possible formation of a Syria "contact group" that might be able to draw up a "roadmap" out of the conflict.

"You cannot resolve it just by focusing on players inside, you need to have the regional and international players involved. They have to be part of the solution. Iran, as an important country in the region, I hope will be part of the solution," Annan said.

Russia had suggested that key regional power Iran would be an ideal member of such a contact group, a suggestion subsequently rejected by the US, UK and France - who accuse the government in Tehran of arming the Syrian military.

The Syrian conflict has divided the UN Security Council, pitting Western and Arab League countries against permanent members Russia and China. They both oppose outside military intervention in Syria.

msh/ch (AFP, AP, dpa, Reuters)