A group describing themselves as anarchists have clashed with police in Athens,
They torched three cars and a bus as well as setting fire to rubbish bins.
It followed an earlier protest by supporters of a colleague currently in jail for a bank robbery who is demanding to be allowed to attended university classes.
The violence comes four days before the anniversary of the death of a 15-year-old in 2008 by police, which sparked weeks of some of the worst riots ever seen in Athens .