Families leave their homes in Taldou, near Houla

DAMASCUS: Forces loyal to Syrian President Bashar al-Assad “massacred” about 100 people including women and children, the opposition said, as the US demanded a full transfer of power in the country.

The call by Secretary of State Hillary Clinton set the stage for a renewed diplomatic stand-off over Syria, after Russia and China said they were strongly against intervention and regime change.

If reports of the killings in the central province of Hama prove accurate they will rank among the worst atrocities in Syria’s 15-month uprising against Assad's embattled regime.

“We have 100 deaths in the village of Al-Kubeir, among them 20 women and 20 children,” Mohammed Sermini, spokesman for the exiled opposition Syrian National Council, told AFP.

He accused the regime of being behind the “massacre”.

Other sources also reported a mass killing had taken place in the same area, including the Syrian Observatory for Human Rights, which tentatively put the number of dead at 87.

The Syrian government on Thursday denied responsibility, saying in a televised statement: “What a few media have reported on what happened in Al-Kubeir, in the Hama region, is completely false.”

“A terrorist group committed a heinous crime in the Hama region which claimed nine victims. The reports by the media are contributing to spilling the blood of Syrians,” the statement said.

But the Britain-based Observatory said in a statement that pro-regime shabiha militia armed with guns and knives carried out the “new massacre” at a farm after shelling by regular troops.

“What is certain is that dozens of people died, including women and children,” the watchdog’s Rami Abdel Rahman told AFP.

Both Sermini and the Observatory urged UN observers to immediately head to the region to investigate.

The reports come after at least 108 people were killed in a two-day massacre that began on May 25 near the central town of Houla, most of them women and children who were summarily executed, according to the United Nations.

News of the new incident came after Russia and China said they were “decisively against” intervention or regime change in Syria, as Arab and Western calls mounted for strong international action in the conflict.

The United States endorsed an Arab proposal to invoke the UN Charter’s tough Chapter VII, while refraining from supporting its powers to initiate military intervention.

Meanwhile Clinton, who has voiced mounting frustration with the Chinese and Russian positions, sought to mobilise support in Turkey, calling on the international community to “close off the regime's economic life lines”.

“We can’t break faith with the Syrian people who want real change,” said a State Department official who briefed reporters on Clinton's meeting in Istanbul with officials from 16 regional and European powers.

Clinton set forth “essential elements and principles that we believe should guide that post Assad transition strategy, including Assad's full transfer of power,” the official said.

Other elements include “the establishment of a fully representative and inclusive interim government which leads to free and fair elections, a ceasefire to be observed by all and equality for all Syrians under the law”, the official said.

But Clinton’s Russian counterpart Sergei Lavrov warned regime change in Syria would lead the Middle East to “catastrophe”.

Beijing and Moscow said after two days of talks between Russian President Vladimir Putin and Chinese leaders that they strongly opposed intervention and regime change.

“Russia and China are decisively against attempts to regulate the Syrian crisis with outside military intervention, as well as imposing... a policy of regime change,” a joint statement said.

Speaking in the Chinese capital, Lavrov urged the international community to resist calls from the exiled opposition to help oust Assad's regime.

Opposition groups “outside Syria appeal to the world community more and more to bomb the Assad regime, to change this regime. This is very risky, I would even say it is a way that will bring the region to catastrophe”, he said.

Lavrov hit out at the rebel Free Syrian Army's announcement it was no longer bound by UN-Arab League envoy Kofi Annan's six-point peace plan, and proposed a high-level conference with the participation of Iran among other powers.

His proposal was given a cool reception by Clinton, as well as by the French and British foreign ministers.

Russia and China have vetoed two Security Council resolutions against Assad's regime, but backed Annan’s blueprint to end the conflict in which more than 13,500 people have died since March 2011, according to the Observatory.

The Annan plan was supposed to begin with a ceasefire from April 12 but doubts have emerged about its effectiveness as violence has raged on despite the deployment of nearly 300 UN observers.

In other violence, rebels went on the offensive in and around Damascus and 46 people were killed across the country, the Observatory said.