DAMASCUS - The head of UN observers mission in Syria Saturday condemned the "tragic and brutal" massacre in Syria that left more than 90 people dead, including 32 children, warning the prolonged violence could lead the country to a civil war.

Top UN officials and some countries joined the chorus of condemnation amid mounting calls for a halt to all violence.

Relentless crime

Maj. Gen. Robert Mood, head of the United Nations Supervision Mission in Syria, issued a statement on Saturday in which he said UN observers went earlier Saturday to Houla, where they found more than 32 children under the age of 10 and over 60 adults were killed.

"This is by whatever standard a terrible tragedy for each family, for the village and for the Syrian people," he said. "This indiscriminate and disproportionate use of force is unacceptable and unforgivable."

"The death of 32 children is something that is absolutely deplorable," The Norwegian general added. "The killing of innocent children and civilians needs to stop."

Mood said the circumstances that led to the "tragic killings" remained unclear, but he urged the Syrian government and the opposition to cease all forms of violence. "This is exactly what we need to stop, to bring the situation forward on a political solution."

Earlier in the day, Syrian state TV showed footage of the carnage in Houla, a group of villages northwest of the central city of Homs, blaming armed extremists for the slaughtering there, contrary to some activists' accusation that government troops carried out the massacre.

The TV said that more massacres were committed Saturday by armed groups at al-Shomarieh town in Homs and more than 10 people were killed.

Meanwhile, Syrian opposition's main coalition, Turkey-based Syrian National Council, said more than 110 people were killed by pro-government militia in Houla.

An amateur video posted online showed people in Houla burying dozens of their relatives in mass graves, and also some bloodied bodies of children, some with their skulls split open.

Media reports said severe clashes took place overnight Friday in Homs, forcing several families to flee Houla on Saturday.

The ongoing violence continued unabated despite the deployment of more than 250 UN observers, who began to arrive in Syria last month to monitor the sloppy cease-fire truce.

Analysts worry that the situation in Syria has escalated into sectarian conflicts and revenge crimes in a country where Sunnis make up 70 percent of its 24 million inhabitants ruled by the Alawite minority, an offshoot of Shiite Islam.

International condemnation

Mood condemned "in the strongest possible terms the brutal tragedy," saying "Those who use violence for their own agenda will create more instability, more unpredictability and may lead the country to a civil war."

Meanwhile, UN Secretary-General Ban Ki-moon and UN-Arab League joint envoy Kofi Annan on Saturday strongly blasted the killings, saying "This appalling and brutal crime involving indiscriminate and disproportionate use of force is a flagrant violation of international law and of the commitments of the Syrian government to cease the use of heavy weapons in population centers and violence in all its forms."

In a joint statement, they said artillery and tank shells were fired at a residential neighborhood.

"Those responsible for perpetrating this crime must be held to account," they stressed, demanding the Syrian government immediately cease the use of heavy weapons in population centers and reiterating that all kinds of violence in Syria must cease.

Annan is contacting the Syrian authorities to convey in the clearest terms the expectations of the international community, and he will also do so during his forthcoming visit to Syria, according to the statement.

Also on Saturday, the UN Children's Fund (UNICEF) said the UN agency was outraged by the killing of 32 children.

"This outrageous crime against such young children who have no part in these battles points to a new urgency in finding solutions to the Syrian conflict," its spokesperson for the executive director Sarah Crowe said. "Such a massacre cannot go unpunished."

US Secretary of State Hillary Clinton said in a statement that "the United States condemns in the strongest possible terms" the massacre, which "involved a regime artillery and tank barrage on a residential neighborhood."

She said the United States would work with the international community to intensify "pressure on Assad and his cronies, whose rule by murder and fear must come to an end."

From Britain, Foreign Secretary Eilliam Hague said his country was in urgent talks with allied countries "on a strong international response," and that it would seek an urgent session of the Security Council in response to what he called "credible and horrific reports."

He said the priority was "to establish a full account of this appalling crime and to move swiftly to ensure that those responsible are identified and held to account."

Meanwhile, France called for an immediate implementation of Annan's six-point plan, saying that it would summon a meeting of the Friends of Syria group and hold a talk with Annan on Sunday.