Reports say protesters poured into the streets of cities across Syria after weekly Muslim prayers on Friday to demand the ouster of President Bashar al-Assad's regime.
Referring to the death of Libya's longtime ruler Muammar Qaddafi the previous day on October 20, the protesters shouted slogans warning Assad that his regime will be the next to fall.
Activists said security forces fired on protesters, killing at least 13, most of them in the central city of Homs.
The UN estimates that more than 3,000 people have been killed in a security crackdown since protests against Assad's regime began seven months ago.
The UN has warned of the danger of a full-blown civil war as an increasing number of defectors from the army join the opposition.
compiled from agency reports