DAMASCUS, Syria — The Syrian government on Sunday denied responsibility for a string of villages that left more than 90 people dead, blaming the killings on “hundreds of heavily armed gunmen” who also attacked soldiers in the area.

Friday’s assault on the central area of Houla was one of the bloodiest single events in Syria’s 15-month-old uprising, and gruesome images of dozens of children killed in the attacks prompted a wave of international outrage.

The U.N. said 32 children under the age of 10 were among the dead and issued a statement appearing to hold the Syrian regime responsible. Persistent violence has cast doubt about the future of international efforts to halt 14 months of bloodshed between the regime and forces fighting against it.

Activists from Houla said Saturday that regime forces had peppered the area with mortar shells after large demonstrations against the regime on Friday. That evening, they said, pro-regime fighters known as shabiha stormed the villages, gunning down men in the streets and stabbing women and children in their homes.

Foreign Ministry spokesman Jihad Makdissi disputed those accounts, saying Syria is being subjected to a “tsunami of lies.”

“We categorically deny the responsibility of government forces for the massacre,” Makdissi said Sunday during a news conference in Damascus.

Giving the regime’s version of events, Makdissi said “hundreds of heavily armed gunmen carrying machine guns, mortars and anti-tank missiles” launched a simultaneous attack against five army positions from several locations, starting about 2 p.m. and continuing for nine hours. Three soldiers were killed and 16 were wounded, he said.

“There were no Syrian tanks or artillery in the vicinity” of Houla, Makdissi said. He said that gunmen used anti-tank missiles and “Syrian troops retaliated in defense of their positions.”

“Children, women and other innocent people were killed in their homes, and this is not what the Syrian army does,” Makdissi said. “The method of killing was brutal.”

Makdissi said a committee was set up to investigate the attack, and results should be out within three days. He added that Kofi Annan, the joint U.N.-Arab League envoy, will fly to Syria on Monday.

But a senior Arab League official said Syria has denied permission for Annan’s deputy to travel to Damascus. Syria insisted the decision against former Palestinian Foreign Minister Nasser al-Kidwa was not personal, but rather because it did not want to deal with the Arab League, the official said on condition of anonymity because of the sensitivity of the subject.

The Houla attacks sparked outrage from American and other international leaders, and renewed concerns about the relevance of a 6-week-old international peace plan that has not stopped almost daily violence. The U.N. put the death toll weeks ago at more than 9,000. Hundreds have been killed since.

U.N. observers, among more than 250 who were dispatched in recent weeks to try to salvage the cease-fire plan, found spent artillery and tank shells at the site Saturday — a finding that points toward the government’s heavily armed mechanized units.

On Sunday, Britain’s Foreign Secretary William Hague said he would summon Syria’s most senior diplomat in the U.K. on Monday so the Foreign Office’s political director could “make clear our condemnation of the Syrian regime’s actions.”

Syria says the Arab League has become a tool of the West. The group suspended Syria’s membership and approved sanctions against it late last year.

Kuwait, which currently heads the 22-member Cairo-based Arab League, announced it is calling for an Arab ministerial meeting that aims to “take steps to put an end to the oppressive practices against the Syrian people.”

Late Saturday, Foreign Minister Sheik Abdullah bin Zayed Al Nahyan of the United Arab Emirates condemned the killings in Houla and called for an urgent meeting of the Arab League.

Activists said government troops shelled residential areas in other areas of central Syria on Sunday.

The shelling hit neighborhoods in the central city of Hama and the rebel-held town of Rastan north of Homs, the Local Coordination Committees and the Britain-based Syrian Observatory for Human Rights said.

The two groups also reported clashes between troops and rebels in Hama, in the Damascus suburb of Harasta and in the capital’s central Midan district. They said a bomb struck a security vehicle in the capital’s upscale district of Mazzeh, near a military airport, according to the LCC.

The Observatory said the vehicle bombing caused casualties but did not have further details.

Damascus is tightly controlled by regime forces but has been hit by a wave of bomb blasts over recent months that killed scores of people. Most of the blasts have targeted Syrian security agencies.