GGS NEWS : Special envoy Kofi Annan is to visit Damascus on Monday, the day after the UN condemned Syria for its use of heavy weaponry in the town of Houla, where at least 108 people were killed.
Forty-nine children and 34 women were among Friday’s dead, the UN said.
Syria’s ambassador to the UN rejected what he called a “tsunami of lies” from some Security Council members.
Meanwhile, UK Foreign Secretary William Hague is going to Russia, which views Syria as a vital ally in the region.
The BBC’s Daniel Sandford, in Moscow, says Mr Hague will argue that this could be the last opportunity to secure a “political transition” in Syria and avoid all-out civil war.
Russia and China have blocked previous attempts to impose UN sanctions on Syria.
The Syrian ambassador to London has also been summoned to the Foreign Office to hear the British government’s condemnation of the massacre in Houla.
Fighting in Syria has continued despite the deployment of some 280 UN observers monitoring a ceasefire brokered by Mr Annan.
Opposition activists said at least 30 people were killed on Sunday when the army shelled the central city of Hama. These reports cannot be independently verified, as Syria severely restricts journalists’ freedom of movement.
The BBC’s Jim Muir in neighbouring Lebanon say there is no sign that the Syrian government’s behaviour on the ground has changed as a result of the Houla massacre.
Sunday saw thousands of activists take to the streets in protest at events in Houla.
‘Severe physical abuse’
On Sunday, the Security Council unanimously adopted the non-binding statement, calling for the Syrian government to withdraw its heavy weaponry from residential areas and return them to barracks.
“The members of the Security Council condemned in the strongest possible terms the killings… in the village of (Houla), near Homs, in attacks that involved a series of government artillery and tank shellings on a residential neighbourhood,” the statement said.
“The members of the Security Council also condemned the killing of civilians by shooting at close range and by severe physical abuse,” the statement continued.
“Such outrageous use of force against civilian population constitutes a violation of applicable international law.”
But Syria’s UN ambassador, Bashar Jaafari, accused some members of the council of trying to mislead the world about Syria’s role in the massacre.
“Neither [UN observer mission head Maj Gen Robert] Mood nor anybody else told the Security Council in the informal session that he would blame the Syrian government forces for what happened.
“It is really pitiful and regrettable that some members of the council came out just a few minutes after Gen Mood had finished his briefing to mislead you, to tell you lies about what happened,” he said.
Mr Jaafari said there had been deaths, but said they had been due to close-range assassinations rather than a result of shelling. Syria has blamed the massacre on “terrorists”.