Syrian security forces opened fire during one of the largest anti-government protests so far in the 10-week uprising, and activists said at least 34 people were killed Friday in a city where thousands died in a failed 1982 revolt against the regime.

President Bashar 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.

The regime 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 organizes 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.

'It is a real massacre'

Rami Abdul-Rahman, director of the Syrian Observatory for Human Rights, said tens of thousands of people were protesting in Hama when security forces opened fire. He said the Hama protest was among the largest yet in the uprising that began in mid-March.

He added that security forces shot dead one person in the village of Has in the northern province of Idlib.

"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.

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.

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.

'There are many killed and wounded people; the hospital is full. I fled the area, but I can still hear sporadic gunfire.'—Eyewitness in Hama

As the Friday Muslim prayers ended, 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.

Rights groups say more than 1,100 people have been killed since the revolt against Assad erupted in mid-March.

An eyewitness in Hama reached by The Associated Press said there were around 150,000 demonstrators, an unprecedented number if confirmed. He 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."

74 killed since Saturday

Syrian troops also pounded the central town of Rastan with artillery and gunfire for a seventh day, killing at least two people. The Local Co-ordination Committees, which helps organize and document Syria's protests, says troops also opened fire on residents fleeing the town.

Friday's deaths bring the toll in Rastan and nearby Talbiseh to 74 killed since last Saturday.

The opposition had called for Friday's nationwide rallies to commemorate the nearly 30 children killed by Assad's regime during the uprising.

In the southern city of Daraa, 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 regime also released hundreds of political prisoners this week after Assad issued a pardon. The Syrian Observatory for Human Rights said leading Kurdish politician Mashaal Tammo and Muhannad al-Hassani, who heads the Syrian Organization for Human Rights, were released Thursday.

Tortured boy becomes symbol

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.

Human rights activist Mustafa Osso said Syrian security forces opened fire Friday at demonstrators in the southern village of Inkhil, but it was not clear if there were any casualties.

A Syrian activist said authorities cut internet service in several parts of the country, apparently to prevent activists from uploading footage of the protests and the government crackdown and from organizing new resistance. In Damascus, several people contacted over the phone said the internet was down.

Video surfaced earlier this week on YouTube, Facebook and websites of 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.