Clashes broke out between protesters and police in Athens on Wednesday, as thousands demonstrated after a musician was murdered by a suspected neo-Nazi, the Athens News Agency reported.
Police fired tear gas at a small group of anti-fascism protesters who pelted them with wooden sticks and stones in Keratsini, western Athens, the agency said.
In all, around 5,000 people took to the streets of Keratsini, according to a police source, and most protested peacefully.
Pavlos Fyssas, a 34-year-old left-wing hip hop singer, was stabbed to death early on Wednesday morning outside a Keratsini cafeteria.
Police said a 45-year-old alleged member of the Golden Dawn neo-Nazi group arrested at the scene of the killing had confessed to stabbing Fyssas, who wrote music under the nickname Kilah P.
Later in the day, the suspect's wife was also arrested for giving false evidence to the police during the investigation.
Golden Dawn has denied any connection to the killing, which came a few days after a group of Communists were beaten by suspected neo-Nazis.
Government spokesman Simos Kedikoglou blamed the killing on Golden Dawn, condemning the group's "raw violence" and calling on other parties to "raise a barrier to the vicious circle of tension and violence".
Earlier in the day, some 20,000 people marched in Athens, Thessaloniki and other cities in a separate protest against a government overhaul of the public sector.