Balaclava-clad men started hurling Molotov cocktails and other objects at police officers in the centre of Athens shortly after 1:30 p.m. when the largest part of the protest march over the train accident in Tempi had passed through Syntagma Square.
The special SWAT units used stun grenades and tear gas to dispel the attacking youths.
The incidents initially started on the lower side of Syntagma Square but quickly spread to the upper side of the square, in front of the Parliament.
The hooded men then started heading towards Omonia square through the University, continuing to throw stones, marbles, and objects at the policemen who were pursuing them. The rioters also set fire to some rubbish bins.
Another group of rioters moved to the Academy where they continued to throw objects at the police who responded with stun grenades.