Syrian security forces have opened fire on one of the largest anti-government protests in the 10-week uprising so far, leaving at least 34 people dead in the central city of Hama, activists said.
The Syrian Observatory for Human Rights said the victims were killed on Friday as security forces dispersed a rally of more than 50,000 people in a city where thousands died in a failed 1982 revolt against the government.
The deaths came as president Bashar al-Assad's forces renewed their assault on towns seen as key to the demonstrations calling for an end to his family's 40-year rule.
Rami Abdul-Rahman, director of the Syrian Observatory for Human Rights, said the Hama protest was among the largest yet in the uprising that began in mid-March. He said security forces also shot dead one person in the village of Has in the northern province of Idlib.
The violence began after Muslim prayers ended, as worshippers left the mosques and marched in cities, towns and villages. Syrian security forces dispersed some, mostly using batons, tear gas and water cannons and fired live ammunition in at least two locations in southern and northeastern towns.
"It is a real massacre. It is terrorism by itself and they want the people to stay silent," said an activist in Hama. The activist, who like many involved in the protests requested anonymity to avoid reprisals, said hospitals were calling on people to donate blood.
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In 1982, Assad's father and predecessor Hafez Assad, crushed a Sunni uprising by shelling Hama, killing 10,000 to 25,000 people, according to Amnesty International estimates.
On Friday, an eyewitness in Hama reached by The Associated Press news agency described a chaotic scene, with security forces firing tear gas and live ammunition, and snipers shooting from the rooftops as people fled.
"There are many killed and wounded people, the hospital is full," he said. "I fled the area but I can still hear sporadic gunfire."
Syria's state-run TV said three "saboteurs" were killed when police tried to stop them from setting a government building on fire in Hama. The Syrian government blames armed gangs and religious extremists for the violence.
The government also cut internet service across most of the country, a potentially dire blow for a movement that motivates people with graphic YouTube videos of the crackdown and loosely organises protests on Facebook pages.
The Internet shutdown, if it continues, could also hamper the movement's ability to reach the world outside Syria, where the government has severely restricted the media and expelled foreign reporters, making it nearly impossible to independently verify what is happening there. Still many activists found alternate ways to log on and upload videos, such as satellite connections.
Syrian troops also pounded the central town of Rastan with artillery and gunfire for a seventh day on Friday, killing at least two people.
The Local Co-ordination Committees, which helps organise and document Syria's protests, said troops also opened fire on residents fleeing the town.
Friday's protests reached nearly throughout the country, from a village in the south to a city in the northeast. Protesters even gathered in several Damascus suburbs, though the capital has not seen the kind of disruption as many other cities.
Friday's deaths bring the toll in Rastan and nearby Talbiseh to 74 killed since last Saturday. Rights groups say more than 1,100 people have been killed since the revolt against Assad erupted in mid-March.
The opposition had called for Friday's nationwide rallies to commemorate the nearly 30 children killed during the uprising.
In the southern city of Deraa, where the uprising began 10 weeks ago, scores of people rallied in the city's old quarter, chanting "No dialogue with the killers of children," an activist said.
The protesters were referring to a decree by Assad to set up a committee tasked with leading a national dialogue.
The call for protests came after a video surfaced earlier this week on YouTube, Facebook and websites featuring Hamza al-Khatib, a 13-year-old boy whose tortured and mutilated body was returned to his family weeks after he disappeared during the protests.
The boy has since become a symbol to Syria's uprising and many people carried his posters during anti-regime rallies this week.