'Many dead' in fresh Homs attacks
Activists believe as many as 47 people have been killed in an attack by pro-government militia in the embattled Syrian city of Homs.
Women and children are among those reported to have been tortured and killed on Sunday night in the neighbourhood of Karm el-Zeytoun.
The Syrian government acknowledged the deaths, but blamed "armed terrorists".
The attack happened hours after UN-Arab League peace envoy Kofi Annan ended his two-day mission to Damascus.
Homs has been under assault for weeks as government forces have tried to root out rebel fighters. Parts of the city are devastated.
Syria is being discussed at a meeting of UN Security Council foreign ministers in New York.
UK Foreign Secretary William Hague said that the Security Council had so far failed in its responsibility to the Syrian people "in the eyes of the overwhelming majority of the world".
"It should be possible for the Council to call for an immediate end to the brutal repression and violations of human rights; to demand an end to all violence and immediate and unhindered humanitarian access," he said.
He called on the Council - which include Russia and China, who have opposed previous resolutions on Syria - to "adopt a resolution containing these essential elements".
Mr Hague's comments echoed those of the UN Secretary-General Ban Ki-moon who said the Syrian government had "failed to fulfil its responsibility to protect its own people and instead has subjected its citizens in several cities to military assault and disproportionate use of force".
Mr Ban said the Council must unite "to help Syria pull back from the brink of a deeper catastrophe".
Hundreds of families fled the Karm el-Zeytoun area of Homs on Monday after reports of the attack in their neighbourhood overnight, the British-based Syrian Observatory for Human Rights said.
One activist in Homs, Hadi Abdallah, told AFP the bodies of 26 children and 21 women were found, some with their throats slit and others bearing stab wounds.
Both the opposition Syrian Revolution General Commission (SRGC) and the Local Co-ordination Committees (LCC), an activist network in Syria, put the toll at 45.
The SRGC said that some of the victims had been burned alive with heating fuel poured over them and others had their necks and limbs broken.
Mulham al-Jundi, an opposition activist and member of the SNC, said Karm el-Zeytoun was experiencing a military bombardment similar to the one seen in Baba Amr district in recent weeks.
He told the BBC government troops were firing rockets from tanks outside the neighbourhood, then going in and "killing the families who stay inside these areas".
Reports are difficult to verify because of tight restrictions on independent media operating in Syria.
Footage posted on YouTube, said to show the bodies of men, women and children killed in the attack, made for grim viewing, said the BBC's Jon Donnison in neighbouring Lebanon.
In one video, at least 11 bodies can be seen, including at least four young children covered in blood, he adds.
Syrians have been urged to go on strike on Tuesday in a "day of mourning" organised by the LCC.
The LCC said last Thursday that at least 44 people - including 20 from one family and 16 from another - were killed in the Jobar district of Homs.
Syrian state television accused "armed terrorist gangs" of carrying out the killings, saying the bodies had been filmed in an effort to discredit the government.
Both the LCC and the Observatory blame the pro-government Shabiha militia for the attack.
The Shabiha has been blamed for many of the atrocities carried out since the uprising began nearly a year ago.
Activists say their presence has allowed the government to deny any involvement in the most brutal actions against protesters.
Kofi Annan left Syria on Sunday after two days off talks with President Bashar al-Assad, saying he was "optimistic" about the possibility of a ceasefire, humanitarian access to affected areas and future political dialogue.
He said he had presented Mr Assad with "concrete proposals" to bring an end to the bloodshed, but gave no hint that a deal was imminent.