An opposition group reported last Thursday that government forces have carried out a “massacre” in Hama province, killing 220 people there. Most of the killings occurred in the village of Tremseh, the Local Coordination Committees of Syria said.

The day’s death toll nationwide reached 287, making it the bloodiest day in Syria since the uprising against the government began 16 months ago, the opposition group told CNN.

As it has done consistently, Syrian state television blamed “armed terrorist groups” for the killings, accusing them of having shot “indiscriminately at the people of Al-Tremseh village in Hama suburbs. And after calls from the people of the village, the security forces clashed with the terrorist groups, arresting a number of them and confiscated their weapons.”

Activists in the city of Hama told CNN that witnesses inside Tremseh told them by telephone that Syrian military forces had launched a full-scale attack against the opposition Free Syrian Army inside the town, which was surrounded by government tanks and artillery.

The forces had shelled the town continuously from 5 a.m. until noon, when their tanks entered the village, three activists told CNN separately. None of them was willing to be identified publicly.

Syrian army forces, whose numbers were bolstered by the pro-regime militias called “shabeha,” accompanied the tanks into Tremseh, they said. As the government forces rained artillery rounds into the town, a number of village residents fled their houses into the streets, where many of them were shot dead by the government militias, the activists told CNN in separate telephone interviews.

CNN is not able to confirm their accounts because Western journalists have limited access to the country.

The violence was also occurring farther south, in the capital, where 12 people were killed, the LCC said. The Damascus neighborhood of Shaghour was under siege by government forces, whose snipers were occupying the roofs of buildings, the LCC said.

In the capital city’s suburb of Naher Aisha, government forces opened fire on a group of people who were demonstrating in condemnation of the Tremseh killings, LCC said.

The carnage came as a top Syrian diplomat who defected Wednesday said in an interview broadcast Thursday that he has sympathized with the opposition movement since it began in March 2011, but had held out hope that President Bashar al-Assad would change course.

“I am from Day One with the revolution,” Nawaf al-Fares, the former Syrian ambassador to Iraq, told Al Jazeera Arabic. “Due to the political and personal circumstances, just a few people knew about that.”

Al-Fares added, “I had hope, and I was in direct contact with President Bashar. He is now the former Syrian president, because he is a criminal and he is killing the Syrian people.”

Syrian government authorities said al-Fares has been “relieved of his duties.”

Al-Fares is the second high-profile Sunni official to break with the regime in a week. Manaf Tlas, a Republican Guard brigadier general and the son of a former defence minister, defected last week to protest the killing of civilians by government forces.

The moves might be a sign that Sunni allies of the Alawite-dominated regime are displeased with the government’s fierce crackdown on an opposition dominated by Sunnis.

According to the official Syrian Arab News Agency, al-Fares was sworn in as Syrian ambassador to Iraq in 2008.