BEIRUT - More than 90 people, including at least 32 children younger than 10, were killed in a central Syrian village, top UN officials said Saturday, accusing the government of perpetrating the indiscriminate shelling of civilian neighborhoods.

In one of the worst episodes of carnage since the uprising began 15 months ago, Syrian tanks and artillery pounded the village of Houla, near the restive city of Homs, during the day, opposition groups said. Then late at night, soldiers and progovernment fighters stormed the village and killed families in their homes.

Amateur videos said to be taken in the aftermath of the assault showed row after row of victims, many of them small children with what appeared to be bullet holes in their temples. Other videos showed gruesome shrapnel wounds caused by what activists said was a barrage of shelling that started Friday in response to demonstrations after the weekly prayer service and that continued Saturday.

UN monitors visiting the village Saturday counted at least 92 bodies and found spent tank shells, which they cited as evidence that the Syrian military had violated its part of a truce in firing heavy artillery at civilians. A UN statement said the observers confirmed that “artillery and tank shells were fired at a residential neighborhood.’’

International officials largely blamed the government.

Ban Ki-moon, secretary general of the United Nations, and Kofi Annan, his predecessor and envoy to Syria, condemned the attack.

“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,’’ the top UN officials said in a statement. They called on Syria to stop using heavy weapons in population centers and for all sides to cease violence.

The White House said the attack was “a vile testament to an illegitimate regime that responds to peaceful political protest with unspeakable and inhuman brutality.’’

Gory images posted online - particularly the scene of rows of dead children smeared with blood - prompted an emotional outpouring of antigovernment demonstrations across Syria and calls for sectarian revenge.

Activists said that much of the slaughter had been carried out by progovernment thugs, or “shabiha,’’ from the area. Houla is a Sunni Muslim town, while three villages around it are mostly Alawite, the religion of President Bashar Assad and the core of his security forces. A fourth village is Shi’ite Muslim.

A man in a black knitted mask who appeared in one YouTube video, for example, said it was time “to prepare for vengeance against this awful sectarian regime.’’

The rebel Free Syrian Army, the loose federation of armed militias across the country, issued a statement saying it was no longer committed to the UN truce because the plan was merely buying time for the government to kill civilians and destroy cities and villages.

“We won’t allow truce after truce, which prolongs the crisis for years,’’ the statement said.

The Syrian government blamed “terrorists’’ - its catch-all phrase for the opposition - for killing the civilians.

State television repeatedly broadcast pictures of members of one household that had been massacred, calling it “part of the ugly crimes that the terrorists are committing against the Syrians with the financial support of some Arab states and others.’’

SANA, the state-run news agency, said “armed terrorist groups attacked law-enforcement forces and civilians’’ in the nearby town of Teldo, which prompted security forces to “intervene and engage the terrorists.’’

But the direct accusation from the United Nations, which is monitoring the tattered April 12 cease-fire, rebutted the government’s standard claim that outsiders or their domestic dupes are to blame for the violence.

Syria sharply limits access to the country for foreign correspondents, making independent verification of events there difficult. But there has been a pattern of similar government assaults in recent months against villages sympathetic to the opposition.

Witnesses also said that armed rebels had been in the village, and it was unclear whether there may have been firing on both sides. Although the UN statements called for stopping of violence by both sides, neither suggested that the opposition was involved in the deaths of civilians in Houla.

The massacre also prompted new questions about the continued effectiveness of the truce just as Annan, the architect of the plan, heads to Damascus. The opposition has criticized the truce, and the UN peacekeepers that came with it, as ineffective. There are 271 unarmed military observers on the ground in Syria, nearly the entire contingent of 300 approved by the Security Council, as well as numerous civilian workers.

The observers seemed to have leapt into action, producing a quick and detailed report on the violence. Despite their efforts, as well as the unprecedented step of the United Nations directly accusing the government of perpetrating major violence, the massacre only soured Syrians even more on their presence since the killing took place despite observers being deployed in nearby Homs.

The UN observers reported that in addition to the more than 90 dead, they counted more than 300 wounded, Annan’s spokesman, Ahmad Fawzi, said. Opposition groups put the death toll at about 100 killed, including 50 children.

The UN statement stopped short of accusing the government of responsibility for the entire toll.

General Robert Mood, the head of the UN observer mission in Syria, said in a statement that “the killing of innocent children and civilians needs to stop,’’ but added that the circumstances behind all the deaths remained “unclear.’’

In Washington, Secretary of State Hilary Rodham Clinton focused on what she described as the “vicious assault that involved a regime artillery and tank barrage on a residential neighborhood.’’

“Those who perpetrated this atrocity must be identified and held to account,’’ she said in a statement. “And the United States will work with the international community to intensify our pressure on Assad and his cronies, whose rule by murder and fear must come to an end.’’

Laurent Fabius, the French foreign minister, issued a statement accusing Syria’s government of committing “new massacres’’ and added that France would organize a meeting of the roughly 80-member “Friends of Syria’’ group as soon as possible.

The British foreign secretary, William Hague, said Britain was looking for a strong international response and hoped to convene an “urgent’’ session of the UN Security Council “in the coming days.’’