Kofi Annan, the joint United Nations-Arab League envoy to Syria, has admitted that his peace plan is failing and that the country's future will consist of "brutal suppression, massacres, sectarian violence and even all-out civil war" if it continues on its current path.
In a speech to the U.N. General Assembly on Thursday, Annan confirmed that massacres of civilians have taken place in the towns of Houla and al-Qubayr. While not assigning blame for the mass killings, the former U.N. secretary general said that the government, not the armed opposition, had the "first responsibility" to halt violence.
"I must be frank and confirm that the (six-point peace) plan is not being implemented," he said.
He said that despite urging President Bashar al-Assad to "make a strategic decision to change his path," the government's shelling of cities had continued, and government-backed militias "seem to have free reign, with appalling consequences."
"The international community has united, but it now must take that unity to a new level," Annan said. "It must be made clear that there will be consequences if compliance is not forthcoming."
Secretary-General Ban Ki-moon, speaking before Annan, said U.N. monitors seeking to reach al-Qubayr on Thursday, the day after the massacre, came under fire from small arms.
Earlier, Norwegian General Robert Mood said in a statement that the observers - who are authorised by the Syrian government - were being stopped and in some cases turned back at Syrian army checkpoints.
Syria's U.N. envoy, Bashar Jaafari, said that the government was investigating the massacres and that international television stations had broadcast false images of the victims. He accused the armed opposition of assassinations, bombings and massacres and alleged that foreign countries were funnelling money to Salafist and terrorist groups.
"The government of Syria extends political reconciliation to all forces whose hands are not stained by blood," he said.
He said some U.N. patrols were also being stopped by civilians, and that some residents in the area of the alleged massacre said the observers would be at risk if they entered.
The U.N. mission dispatched observers after receiving reports of a mass killing in al-Qubayr, a small village. Opposition activists said that pro-government armed groups backed by security forces killed scores of people there.
The Local Co-ordination Committees, a Syrian activist network, and the UK-based Syrian Observatory for Human Rights (SOHR) said that more than 86 people had died. Syria's government denied any role in the killings.
"What a few media have reported on what happened in al-Qubayr, in the Hama region, is completely false," the government said in a statement on official television.
"A terrorist group committed a heinous crime in the Hama region which claimed nine victims. The reports by the media are contributing to spilling the blood of Syrians," the statement said.
Mousab al-Hamadee, an activist in Hama, told Al Jazeera that the attack bore similarities to last month's massacre in Houla, and said the government was seeking to create an "atmosphere of terror and intimidation".
He said the Syrian army had prepared the way by shelling the area before pro-government gangs descended on the village.
"Most of victims were burnt in their houses, many of them were slaughtered by knives in a very ugly way," he said, adding that women and children were among the dead.
He also criticised the role of the U.N. monitoring mission.
"Unfortunately they do nothing to protect us, they just come the next day after the massacres to film the corpses and see how we bury our victims … They are just watching us die," he said.
Manhal Abu-Bakar, another Hama-based activist, told Al Jazeera that Syrian tanks began shelling al-Qubayr on Wednesday afternoon. Pro-government militias from nearby villages then drove into the village, executing some people in a manner similar to the killings carried out in Houla on May 25, he said.
"There were 35 persons from one family. Those persons have all been killed and most of them are women and children," he said.
Reports of the alleged massacre prompted the opposition Syrian National Council to issue a statement calling on fighters aligned with the anti-government Free Syrian Army to "escalate battlefield action" to ease pressure on civilians "under siege, shelling and assaults in the provinces of Hama, Latakia and Homs".
On the diplomatic front, Western and Arab countries have met in Istanbul, Turkey, to discuss the crisis in Syria.
A U.S. official said Secretary of State Hillary Clinton had told the group that a transition in the country should include a "full transfer of power" from Assad, the creation of a fully representative interim government, and free and fair elections.
France said it would host a full Friends of Syria meeting in Paris on Jul. 6, while France and the UK rebuffed a Russian proposal for an international conference on Syria that would include Iran, Damascus' key ally.
"I think the inclusion of Iran in any such group would probably render it unworkable," said William Hague, the British foreign secretary.
"This is a country that is supporting some of the unacceptable violence and supporting the Syrian regime in what it is doing to the Syrian people and that would cause a great difficulty."