Police intervened as protesters from the left and right clashed
Five immigrants have been injured after far-right demonstrators tried to storm a disused courthouse in Athens occupied mainly by illegal migrants from Africa.
Dozens of protesters hurled stones and fireworks at the eight-storey building on Saturday night, while those living inside threw bricks and masonry slabs.
Police said nine officers were also injured in the violence.
Three youths were arrested over the attack, which came after a march by the anti-immigrant Golden Dawn group.
The protesters waved banners reading "Foreigners mean crime" and "We have become foreigners in our own country".
Left-wing groups staged a counter-rally nearby and riot police were deployed to keep the two sides apart.
Petrol bombs and stones were thrown between the two groups, and the violence continued when anti-immigrant protesters descended on the old courthouse.
The Associated Press news agency reports that hundreds of immigrants live in squalid conditions in the building, amid piles of fetid rubbish and human waste without electricity or running water.
Fouad, a 33-year-old Moroccan immigrant living in the building, told AP that he could not understand why the protesters had attacked.
"We didn't do anything. Why do they treat us like this?" he said.
"The police did nothing. Here in Greece, human rights don't exist."