Pro-regime militiamen swept through farmlands in central Syria slaughtering dozens including women and children, activists said Thursday, June 7 sparking opposition calls for increased military raids by armed rebels, AFP reported.

The latest massacre came as Washington demanded a full transfer of power in Syria, setting the stage for a renewed diplomatic stand-off after Russia and China said they were strongly against intervention and regime change.

The Syrian Observatory for Human Rights said at least 55 people were killed in Wednesday's assault on the Al-Kubeir area of the central province of Hama, and added that UN observers were rushing to the site to check on the massacre.

Earlier tolls from opposition groups had put the death toll at between 87 and 100.

The Observatory was joined by the exiled opposition Syrian National Council (SNC) and the Muslim Brotherhood in blaming the killings on shabiha militiamen loyal to President Bashar al-Assad's regime.

They and activists, citing survivors and witnesses, said the militiamen stormed into the small settlement on Wednesday afternoon armed with guns and knives after regime forces had earlier pounded it with shells.

They then went on a killing spree, hacking, stabbing and shooting residents as they tried to flee.

The Syrian government 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.

The opposition called for stepped up military assaults against regime forces in the wake of the reported massacre.