GENEVA - Syrian forces and pro-government militia accused of committing a massacre in Houla could face prosecution for crimes against humanity, the United Nations said on Friday and rights experts said Syrian authorities had directly ordered torture.UN High Commissioner for Human Rights Navi Pillay called again for the Security Council to refer Syria to the prosecutor of the International Criminal Court (ICC) and for world powers to help implement Kofi Annan's peace plan to end the violence."We hold the Syrian government fully responsible for the slaughter of innocent civilians in Houla," US ambassador Eileen Donahoe told the talks. "Those who committed these atrocities must be identified and held accountable."Separately, the UN Committee against Torture, in findings issued on Friday, said that Syrian forces and allied militias had tortured and mutilated civilians including children under "direct order" from Syrian authoritiesIn a speech read out on her behalf to an emergency session of the UN Human Rights Council, she cited allegations that the Syrian military unleashed a barrage of heavy weapons on the town of Houla a week ago and that shabbiha groups killed dozens of the 106 victims, including women and children."These acts may amount to crimes against humanity and other international crimes and may be indicative of a pattern of widespread or systematic attacks against civilian populations that have been perpetrated with impunity," she said.Pillay, a former war crimes judge, added: "I reiterate that those who order, assist or fail to stop attacks on civilians are individually criminally liable for their actions."The Human Rights Council was set to call on Friday for a full UN inquiry into the massacre after putting initial blame on government bombardment and gunmen loyal to President Bashar Assad, diplomats said.It is the 47-member forum's fourth special session on Syria in a year, raising pressure on his increasingly isolated government.But Syria's ambassador, Faysal Khabbaz Hamoui, accused 600-800 "terrorists" using Israel-made weapons of carrying out the slaughter in Houla so as to "ignite sectarian strife".A Syrian investigation was underway to identify the perpetrators and instigators of the killings, he said, adding: "We will submit their confessions to the whole world."Qatar, Turkey and the United States have submitted a draft resolution for adoption at the session. But the European Union has yet to endorse the text as it wants stronger wording, including a call to refer the case to the ICC, diplomats said.The text condemns "the wanton killings of civilians by shooting at close range and by severe physical abuse by pro-regime elements and a series of government artillery and tank shellings of a residential neighborhood."The Council, which has repeatedly condemned Syria for its crackdown, is likely to adopt the resolution by a wide margin, even if countries including China, Cuba and Russia may vote against it, as in the past, Arab and Western diplomats said.