The U.N. Security Council on Sunday blamed the Syrian government for most of the deaths in a massacre of 116 civilians in the village of Houla, issuing a unanimous statement condemning the killings that was supported by Syria’s staunch allies Russia and China.

The killings on Friday, which included at least 32 children, represented one of the bloodiest single incidents yet in the 14-month-old uprising against President Bashar al-Assad’s rule and have served to highlight the failure of a U.N. monitoring mission to halt the violence, which appears to be steadily rising again.

After meeting in a closed-door emergency session Sunday, the 15-member Security Council issued a statement directly accusing Syria of carrying out the killings “of dozens of men, women and children and the wounding of hundreds more . . . in attacks that involved a series of government artillery and tank shellings on a residential neighborhood.”

The “outrageous use of force” against civilians constitutes a violation of international law and of Syria’s commitment to abide by a U.N.-mandated peace plan, the statement added, calling on Syria to immediately comply with the Security Council resolution endorsing the plan by withdrawing all of its troops and tanks from residential areas.

Russia and China, which have in the past blocked criticism of Syria’s behavior, signed on to the statement, signaling their strongest condemnation yet of the Syrian government. But Russia’s deputy U.N. envoy, Alexander Pankin, told reporters after the session that the events leading up to the incident remained “murky.” He raised the prospect that a “third force” had carried out the killings to undermine the U.N. monitoring mission on the eve of Monday’s visit to Damascus by Kofi Annan, the joint U.N.-Arab League special envoy.

Meanwhile, Germany’s U.N. ambassador, Peter Wittig, said there appeared to be no question that the government was responsible. There is “a clear footprint of the government in this massacre,” he said.

The exact details of the killings remained unclear, with the chief of the U.N. mission in Syria telling diplomats in New York that he believed the majority of the deaths were caused by government shelling, and residents of Houla claiming that most of those killed had been shot, hacked or bludgeoned to death in their homes by pro-government militias.

The U.N. statement noted that some of the victims had been killed by “shooting at close range and by severe physical abuse.”

The Syrian government denied responsibility, saying the killings were the work of “armed terrorists,” a phrase repeatedly used by authorities in Damascus to describe the opposition.

Syrian Foreign Ministry spokesman Jihad Makdissi said at a news conference in Damascus that “hundreds of gunmen” carried out the attacks, according to the official Syrian Arab News Agency. They were armed with “heavy weapons, like mortars, machine guns and antitank missiles, which are newly used in the confrontation with state forces,” he said.

The gunmen killed two Syrian army officers and a soldier, injured 16 and massacred civilians in another village near Houla, Makdissi added, without saying how many people were killed there. He said Syrian tanks were not deployed inside Houla and described their positions outside the village as “defensive.”

Observers verified shelling

Briefing Security Council diplomats by video from Damascus, Maj. Gen. Robert Mood, head of the U.N. Supervision Mission in Syria, said that 116 people are thought to have died in Houla and that U.N. observers who visited the town verified that most appeared to have been killed in shelling by government tanks and artillery.

Mood reported that there were “multiple” Syrian army tanks in the Houla area, contradicting the Foreign Ministry spokesman’s account and in violation of Syria’s commitment to the U.N. peace plan.

He also said there was “clear evidence” of the aftermath of shelling and mortar attacks, according to a diplomat who was at the briefing.

In a letter to the Security Council, U.N. Secretary General Ban Ki-moon said U.N. observers who visited the town saw 85 bodies at a mosque with gunshot and artillery wounds. They also saw more than a dozen other bodies, including those of women and children, some of whom appeared to have suffered “severe physical abuse,” the letter said.

Residents of Houla said most of the victims had been killed at close range by the armed civilians known as the shabiha.

Houla is the name given to a cluster of four small Sunni communities on the northwestern edge of the central city of Homs. It is surrounded by five villages inhabited by members of Assad’s minority Alawite sect. The killers were armed civilians from those villages, residents say, underscoring the danger that Syria’s conflict could descend into sectarian war.

Houla residents have acknowledged that at least two Syrian army officers were killed in clashes that erupted between local rebels and Syrian forces Friday afternoon. But they assert that the government then embarked on a spree of punitive shelling against the village, after which the shabiha stormed homes in the area and randomly butchered men, women and children.

“Some of them were killed by gunshots at close range, some of them were killed with bayonets, and some of them had their heads smashed,” said a Houla resident who uses the alias Hamza al-Omar.

Escalating violence

The conflicting accounts pointed to the difficulty of establishing what is happening in Syria at a time when journalists’ access to the country is restricted and the complexity and scope of the violence appear to be deepening.

A correspondent for Britain’s Channel 4 television who visited Houla on Sunday alongside Syrian troops said that although it was clear the army was present in the village, it was also clear the troops were encountering resistance from armed rebels. He said that the troops were pinned down by fire for several hours and that one soldier was shot.

In his letter to the Security Council, Ban said violence is on the rise again, after a shaky cease-fire that went into effect April 12 had somewhat reduced the bloodshed. “Violence against civilian population and clashes between government forces and armed opposition groups in various parts of Syria have escalated in the past two days,” he wrote.

As the Security Council was meeting, opposition groups reported the deaths of at least 24 people in an intensive bombardment of the city of Hama, another opposition stronghold. But activists in the town said they feared dozens more had been killed in the shelling, which continued late into the night.

Lynch reported from the United Nations.