Syrian opposition activists say more than 150 people died after government forces shelled a village in Hama province.

Activists and witnesses say troops, tanks and helicopters bombarded the village of Tremseh on Thursday. Estimates of the number of deaths are as high as 220.

U.S. Secretary of State Hillary Clinton said Friday that credible reports provided indisputable evidence that the regime deliberately murdered innocent civilians.

Report of the massacre comes as the United Nations Security Council debates imposing tough new sanctions on the Syrian government if it keeps attacking civilians. Russia has once again threatened to veto any sanctions.

Russian media say U.N. special envoy Kofi Annan will visit Moscow on Monday for talks on Syria.