Survivors of the massacre in Syria's Houla region have told the BBC of their shock and fear as regime forces entered their homes and killed their families.
Several witnesses said they hid or played dead to survive.
Most claimed that the army and the feared shabiha militia carried out the atrocities, though the regime insisted "armed terrorists" were to blame.
UN-Arab League envoy Kofi Annan has arrived in Damascus for talks on implementing his peace plan.
Russia, which has twice blocked UN Security Council resolutions backing action against President Bashar al-Assad's regime, said on Monday that both sides bore responsibility for Friday's massacre.
UN observers who visited the Taldou village where the massacre happened said they had found evidence of shelling from government forces.
They also confirmed that some of the 108 victims - many of whom were children - had been killed by close-range gunfire or knife attacks.
Most witnesses who spoke to the BBC said they believed that the army and shabiha militiamen were responsible.
"We were in the house, they went in, the shabiha and security, they went in with Kalashnikovs and automatic rifles," said survivor Rasha Abdul Razaq.
"They took us to a room and hit my father on the head with the back of a rifle and shot him straight in the chin."
Of 20 family members and friends in the house at the time, she said only four had survived.
Another resident, who asked to remain anonymous, said he hid in the attic as gunmen took his family outside and shot them.
"I opened the door, and I saw bodies, I couldn't recognise my kids from my brothers. It was indescribable. I have three children, I lost three children," he said.
Other witnesses told how they were now terrified in case the regime forces came back to the area.
Their accounts have not been independently verified, but the BBC's Jim Muir in neighbouring Lebanon says the stories tally with each other, and with reports from activists on the ground.
Western leaders have expressed horror at the killings, and the UK, France and US have all begun moves to raise diplomatic pressure on the Assad government.
British Foreign Secretary William Hague has flown to Moscow to try to get Russia's backing for harsher measures against the regime.
France is convening another meeting of the so-called Friends of Syria group, which Russia does not take part in.
"The murderous folly of the Damascus regime represents a threat for regional security and its leaders will have to answer for their acts," said President Francois Hollande's office.
Mr Annan arrived in Damascus on Monday and will hold talks with Mr Assad on Tuesday.
He said it was a critical moment, and that he would be having "serious and frank" discussions with Mr Assad, trying to persuade him to take "bold steps" to prove he was serious about peace.
Under Mr Annan's plan, both sides were to stop fighting on 12 April ahead of the deployment of monitors and the government was to withdraw tanks and forces from civilian areas.
But the violence has continued, and on Monday activists reported clashes and deaths in at least seven different parts of the country.
At least 10,000 people have died since protests against the Assad regime broke out in March 2011.