Grainy images from the internet have shown protests that are the biggest threat yet to the authority of Syria’s President, Bashar al-Assad.
Reports from Deraa, near the border with Jordan, say at least four people were killed and hundreds more injured in a crackdown by security forces.
Demonstrations were also held in Damascus and in other towns, answering a call made on a social network site for a so-called “Day of Dignity.” The demand is for more freedom and democracy.
Syria’s ruling elite has indicated a belief that it is immune from uprisings sweeping the Arab world, citing economic liberalisation and a hardline against Israel. Latest events may prove it wrong.