A team of UN observers deployed in Syria to monitor a shaky truce arrived on Saturday in the town of Houla, site of a "massacre" by regime forces in which at least 90 people died, monitors said.
"A team of UN observers arrived in the village of Taldau (on the outskirts of) Houla, to document the crimes committed in the past 24 hours, in violation of the ceasefire," said the Syrian Observatory for Human Rights.
Syrian regime forces have "massacred" more than 90 people, including 25 children, in Houla, in the central province of Homs, the Britain-based watchdog said.
The violence caused residents to flee for safety, the monitoring group noted. "Many people are fleeing Taldau village in Houla," the Observatory said, adding that residents feared new attacks on the town, in the central province of Homs.
Amateur videos posted on YouTube showed horrifying images of children lying dead on the floor, with some of their corpses badly mangled. At least one child had had part of his head blown off.
The Britain-based watchdog condemned the Arab and international communities, describing them as "complicit with the Syrian regime in the Houla massacre."
The international community was "silent in the face of the massacres committed by the Syrian regime," it said.
The Observatory reported that "blasts" were heard in Taldahab, very near Taldau, while the monitors were on the outskirts of Houla.
State news agency SANA reported the UN monitors' arrival in Houla, adding that they had also visited the Sultaniya and Jobar districts of Homs city and the Syrian Arab Red Crescent offices there.
SANA blamed "armed terrorist groups" for the killings in Houla, adding that "clashes led to the killing of several terrorists and the martyrdom of several members of the special forces."
The opposition Syrian National Council urged the UN Security Council to act after regime forces "massacred" what it said was more than 110 people in Houla.
The latest flare-up of violence came as Kofi Annan, the UN-Arab League envoy to Syria who brokered a repeatedly violated ceasefire last month, finalised plans to return to Damascus.
On Saturday morning, demonstrations were staged across Syria to protest the killings in Houla, anti-regime activists said.
In Kfarnabel, in the northwestern province of Idlib, scores of men and women took to the streets to honour the dead, chanting: "We sacrifice our soul and life for you, O people of Houla," according to an amateur video posted on YouTube.
Protesters were also angry with the international community.
One demonstrator held up a sign reading: "Annan is singlehandedly responsible for the Houla massacre," blaming the special UN-Arab League envoy for continued violence.
More than 12,600 people have been killed in Syria since a revolt against President Bashar al-Assad's rule broke out in March 2011, including nearly 1,500 since a UN-backed truce took effect on April 12, according to the Observatory.