The government's TV channel and news agency said "infiltrators" in the southern town of Deraa caused "chaos and riots" and smashed cars and public and private property before they attacked riot police who chased them off. It said a similar demonstration in the coastal town of Banyas dispersed without incident.
Amateur video footage posted on YouTube and Twitter showed large groups of protesters in several cities, but its authenticity could not be immediately be independently confirmed.
Serious disturbances in Syria would be a major expansion of the wave of unrest tearing through the Arab world for more than a month in the wake of pro-democracy uprisings that overthrew the autocratic leaders of Tunisia and Egypt. Syria, a predominantly Sunni country ruled by minority Alawites, has a history of brutally crushing dissent — including a notorious incident in which President Hafez Assad crushed a Muslim fundamentalist uprising in the city of Hama in 1982, killing thousands.
One amateur video posted Friday showed what appeared to be show Syrian government trucks spraying water on marchers. Two others purport to show several thousand men gathering in Banyas and the city of Homs.
A YouTube video claiming to be shot in Banyas showed several thousand demonstrators gathering around an old stone building with a Syrian flag fluttering from its roof. A cluster of men stood on its balcony with a loudspeaker. Amidst chants of "Freedom!" and "There is only one God!," one man shouted out a list of protestors demands — ranging from freedom of expression to allowing Muslim women with face veils to attend school.
In the capital, plainclothes security officers forcefully dispersed about a dozen protesters calling for more freedoms in the country, human rights activists said earlier in the day.
The activists said the protest occurred in the yard of Damascus' famous Ummayad Mosque shortly after Friday prayers. At least two protesters were detained, they said.
The protest was the third small rally broken up in Damascus this week.
Assad's death in 2000 after three decades of authoritarian rule raised hopes of a freer society under his British-educated son and successor, Bashar. Political salons where political and economic issues were openly debated sprang up across the country.
But the "Damascus Spring" as it came to be known was short-lived. In 2001, secret police began raiding the salons, jailing two lawmakers and scores of other activists in the years that followed.
In 2004, bloody clashes that began in the northeastern city of Qamishli between Syrian Kurds and security forces left at least 25 people dead and some 100 injured.
Also Friday, eight Syrian human rights groups said a prosecutor had questioned and charged dozens of demonstrators with hurting the state's image.
The groups said the 32 activists denied the charges. They included four relatives of political prisoner Kamal Labawani, who is serving a 12-year prison sentence.
The activists were detained Wednesday when plainclothes security officers armed with batons dispersed a protest near the Interior Ministry demanding the release of political prisoners.