A Facebook group has called for protests on Friday against President Bashar al-Assad's regime and in solidarity with the southern town of Daraa, where troops and tanks have taken over the streets.
"Friday of Anger, April 29, in solidarity with Daraa," says a notice on the Syrian Revolution 2011 page of Facebook, a motor of the protests in which demonstrators inspired by uprisings elsewhere in the Arab world are seeking greater freedoms.
"To the youths of the revolution, tomorrow we will be in all the places, in all the streets ... we will gather at the besieged towns, including with our brothers in Daraa," said the statement posted online on Thursday.
"We will not leave Daraa isolated," it said, adding demonstrations would also be staged in other flashpoint towns such as Homs in the centre of the country and Banias in the northwest.
Syria has been rocked by increasingly strident pro-democracy demonstrations since March 15 that has shaken Assad's once uncontested rule.
The authorities have resorted to violence to crush the uprising, with human rights activists listing at least 453 civilians killed by security forces across Syria in the past few weeks.
On Monday, between 3,000 and 5,000 troops backed by tanks and snipers swept into Daraa, the epicentre of the protests 100 kilometres (62 miles) south of Damascus, and took over the town.
According to human rights activists, more than 30 people have been killed in the military assault on the agricultural town near the Jordanian border.
Assad on Thursday last week scrapped nearly five decades of draconian emergency rule and abolished the repressive state security court in a bid to placate the protesters.
Testing his promised reforms, they staged protests across Syria the following day, demanding an end to the Baath's grip on political power, the release of political prisoners and the right to protest freely.
However, the security forces cleared demonstrations with tear gas and live rounds, with more than 100 people reported killed and hundreds arrested.