(Adds HRW report, Lavrov quote, Annan in Damascus)
By Khaled Yacoub Oweis
AMMAN, May 28 (Reuters) - Syrian activists said on Monday President Bashar al-Assad's forces had killed at least 41 people, including eight children, in an artillery assault on the city of Hama over the past 24 hours.
The report, which could not be independently verified, comes after the U.N. Security Council condemned the massacre of at least 108 civilians, many of them children, in the Syrian town of Houla on Friday.
Images from Houla of the bloodied bodies of children triggered shock and outrage around the world and underlined the failure of a six-week-old ceasefire plan aimed at stopping the violence.
Opposition sources said Syrian tanks and armoured vehicles opened fire on several neighbourhoods of Hama on Sunday after attacks by rebel Free Syrian Army fighters on roadblocks and other positions manned by Assad's forces.
The Hama Revolution Leadership Council said in a statement: "Tank shelling brought down several buildings. Their inhabitants were pulled out from the rubble." It said five women were among the dead.
Western and Arab states opposed to Assad blamed the Syrian government for the killings in Houla. Damascus said it was the work of "armed terrorist groups".
Russia and China, which have vetoed two Security Council resolutions calling for tougher action against Syria, condemned the massacre but stopped short of blaming Assad's forces.
"China feels deeply shocked by the large number of civilian casualties in Houla, and condemns in the strongest terms the cruel killings of ordinary citizens, especially women and children," Chinese Foreign Ministry spokesman Liu Weimin said.
"The Security Council condemned in the strongest possible terms the killings, confirmed by the United Nations observers, of dozens of men, women and children and the wounding of hundreds more in the village of (Houla), near Homs, in attacks that involved a series of government artillery and tank shellings on a residential neighbourhood," the non-binding U.N. statement said.
"Such outrageous use of force against civilian population constitutes a violation of applicable international law and of the commitments of the Syrian government under United Nations Security Council Resolutions," it said.
British Ambassador Mark Lyall Grant said: "It seems quite clear that the massacre in Houla was caused by heavy bombardment, by government artillery and tanks. The fact is, it is an atrocity and it was perpetrated by the Syrian government."
New York-based Human Rights Watch quoted residents of Houla as saying gunmen in government military uniforms swept through after the artillery barrage, executing men, women and children.
Damascus blamed "armed terrorist groups" for the slaughter.
United Nations sources in Damascus said Kofi Annan, the envoy for a faltering U.N.-Arab League peace plan built around the ceasefire, had arrived in Damascus. Syria's Foreign Ministry said he would hold talks with Assad on Tuesday.
Russia said there was no alternative to the Annan peace plan and ruled out Assad's departure.
It echoed Syrian government claims that insurgents - who have emerged alongside a mass protest movement calling for Assad to go - may have carried out the Houla killings.
"We are dealing with a situation in which both sides evidently had a hand in the deaths of innocent people," Foreign Minister Sergei Lavrov said at a joint news conference in Moscow with British Foreign Secretary William Hague.
Opposition activists said Assad's forces shelled Houla after a protest and then clashed with fighters from the Sunni Muslim-led insurgency fighting the rule of Assad, who belongs to the minority Alawite sect.
His government has said it wants a negotiated solution to the crisis but demands an end to foreign assistance for insurgents, in a veiled reference to Sunni Muslim Gulf powers Saudi Arabia and Qatar, which have called for arming the rebels.
Syria's 14-month-old revolt has become the longest and bloodiest of the Arab Spring uprisings. (Reporting by Khaled Yacoub Oweis, Amman newsroom; Editing by Janet Lawrence)