Britain's Foreign Office says U.K. nationals should consider leaving Syria on commercial flights, after it upgraded warnings about unrest there.
In a statement on Wednesday, the ministry said it had changed its advice "in light of the deterioration in the security situation in Syria."
New protests are expected on Friday, with British diplomats warning that violent clashes are anticipated between local security forces and demonstrators.
Britain has not yet considered providing evacuation flights as commercial airlines are still running services as normal.
The ministry says: "It should therefore be possible for British Nationals to leave if they choose to do so."