Reports from Syria say tanks have been shelling the city of Homs as security forces continue a crackdown on anti-government protests.
At least nine people were reportedly killed there on Wednesday and at least 11 in towns around the southern city of Deraa.
Clashes have also been reported in the northern city of Aleppo, at a protest by about 2000 students at a university campus.
The BBC reports thousands of people have reportedly been arrested and hundreds killed in the crackdown.
The government insists it is pursuing ''armed terrorist gangs''.