Syrian rights groups say at least 34 people were killed after security forces opened fire on a large group of demonstrators in Hama, a stronghold of opposition to President Bashar al-Assad's government.

Activists said shooting broke out after Friday prayers in Hamas, which is about 300 kilometers north of Damascus. Witnesses said thousands of people coming out of mosques took to the streets for a protest rally, and government forces began firing live ammunition.

Demonstrations spread across Syria Friday in Damascus and other cities, following a call by opposition groups to denounce a growing number of casualties among children in recent weeks of the uprising against Mr. al-Assad.

Despite official denials, protest organizers say at least 25 children have died in the recent violence. The list of young victims includes a 13-year-old boy who reportedly was tortured and killed by security forces – an accusation that Syrian authorities dispute.

Hama was the scene of a brutal government crackdown in 1982 that left at least 10,000 people dead, according to rights groups' estimates. President Hafez al-Assad – father of the current president — crushed an uprising against his government in that year.

Unofficial reports say all Internet service stopped in Damascus and several other cities on Friday.

The latest unrest follows a two-day meeting in Turkey of Syrian opposition figures, who called for President Assad's immediate resignation. Opposition figures say they are committed to do whatever is necessary to “bring down” the Assad government and begin planning for new, democratic elections.

In New York Friday, a spokeswoman for U.N. chief Ban Ki-moon says he called for an immediate end to “violent repression” by Syrian forces and for dialogue that leads to comprehensive reforms in the country.