BEIRUT -- Anti-regime activists in Syria said Friday that government gunners rained shells on a poor, farming village before armed thugs moved in, leaving scores of people dead in what rebel backers claim is one of the worse single days of bloodshed in the uprising against Bashar Assad's regime.
The accounts -- some of which claim more than 200 people were killed in the violence Thursday -- could not be independently confirmed, but would mark the latest in a string of brutal offensives by Syrian forces attempting to crush the rebellion.
Much remains unclear about what happened in Tremseh in central Syria and why Assad's troops moved against the isolated village. Amateur videos showed the bodies of 17 people said to have been killed. Local activists, who gave the high death toll, could not provide lists of names, saying they were still being compiled.
But the violence was certain to raise even more doubts about the fraying peace efforts of international envoy Kofi Annan, who said he was "shocked and appalled" by the reports of the attack. He criticized the government for using heavy weaponry in populated areas, a violation of his struggling peace plan meant to end Syria's crisis.
One amateur video posted online late Thursday showed the dead bodies of 15 men lined up on a floor. Some are covered in blood and have wounds to their heads and chests. A second video shows a man's body lying on a hospital gurney.
Yet another video showed a young man wailing over the body of an elderly grey-haired man wrapped in a blanket and lying in the street.
"Come on, Dad. For the sake of God, get up," the man sobs. A boom is heard in the background.
For its part, the Syrian government said more than 50 people were killed when Syrian forces clashed with "armed gangs" that were terrorizing village residents. The regime has referred to those seeking its overthrow as terrorists throughout the 16-month uprising.
The killings in Tremseh, about 15 kilometers (nine miles) northwest of the central city of Hama, reflect the difficulty of getting reliable information on events inside Syria, a country of 22 million people that is about the size of North Dakota and closed to most journalists.
The killings will also likely fuel further debates between world powers that remain sharply divided on what to try next to stop Syria's violence. All previous efforts, including Annan's plan, have failed to quell the bloodshed.
Two activists reached Friday via Skype who said they were in villages near Tremseh gave similar accounts of the previous day's events.
Bassel Darwish said the army surrounded the village early Thursday to prevent people from fleeing and pounded it until early afternoon with artillery and tank shells and missiles from a combat helicopter.
"We saw the events," he said, adding that he was a few kilometers (miles) from the village. "Lots of people tried to get the families out but they weren't able to."
After the shelling, the army entered with pro-government thugs, known as shabiha, who gunned down and stabbed residents in the streets, he said.
Darwish said activists had compiled the names of about 200 dead, but he did not share the list. He said chaos reigned in the area as residents searched for the dead and missing.
Another activist, Abu Ghazi al-Hamwi, said local rebels, often called the Free Syrian Army, tried to fight off the army but couldn't.
"They kept shelling the city and the weapons that the Free Army had were not enough to keep them out," he said. "So they started trying to get out the wounded and the families by clashing in one place to open a way out."
He, too, put the dead at more than 200, but did not provide a list of names. He said many of the dead were killed when a shell collapsed the roof of a mosque where they had sought shelter.
The Britain-based Syrian Observatory for Human Rights said Friday that more than 160 people had been killed in Hama province, most of them in Tremseh, though it had the names of about 40 of them. It said dozens of the dead were rebel fighters and that the bodies of about 30 were totally burned. Others were stabbed.
Another video showed a tank in the street while large booms and gunfire are heard in the background. Activist claims and videos could not be independently verified.
The Syrian government gave a very different story of the Tremseh killing, with the state news agency saying that dozens of members of "armed terrorist groups" had raided the village and were randomly firing on residents.
Security forces clashed with the armed men, killing and capturing many of them, the report said. It said three soldiers and some 50 residents were killed.
The agency provided no photos or videos. Assad's regime considers the country's uprising to be the work of terrorists and extremists, not people seeking reform.
Activists say more than 17,000 people have been killed in the uprising, most of them civilians. The government says more than 4,000 members of the security forces have been killed. It does not provide numbers of civilian dead.