Self-styled anarchists clashed with police in the broader district of Exarchia on Wednesday, for the third night in a row, in the wake of a court ruling rejecting an appeal for release by a jailed terrorism convict.
Wednesday's upheaval occurred shortly before 10 p.m. when a group of hooded youths hurled Molotov cocktails at a police unit in the area.
About an hour later a group of protesters attacked a unit of riot police officers.
Police briefly detained three people who were subsequently released without charge.
In a separate development, a group of hooded youths vandalized the façade of the building housing the city hall of Zografou and scattered leaflets protesting the recent death of a sanitation worker.