Syrian forces have renewed their crackdown on protesters, with activists saying at least 16 people have died.
Friday protests came under fire in the central city of Homs, the capital Damascus, Deir al-Zour in the east and Aleppo and Idlib near Turkey's border.
US Secretary of State Hillary Clinton urged other countries to "get on the right side of history" by cutting ties with the Syrian regime.
Earlier, she called for wider international sanctions on Damascus.
More than 1,700 people have died and tens of thousands have reportedly been arrested since the uprising against the 41-year rule of President Bashar al-Assad's family began in March.
Syrian state television admitted there had been small demonstrations after Friday prayers, but activists said they were far bigger and more widespread.'Intense gunfire'
Friday's highest reported casualties were in Douma, a suburb of Damascus, where a woman and a 16-year-old were named among those who died. Syrian state TV said two security men had been shot dead in the capital.