The rioting has continued for a second day
Masked youths have clashed with police in Athens on a second day of protests to mark the first anniversary of the fatal shooting of a teenager by police.
Police charged the crowds in the Greek capital as protesters threw stones on the fringes of a 5,000-strong student-led march to the city's parliament.
More than a dozen protesters were arrested in the fracas.
Police stations were also attacked as protests were held in other parts of the country.
More than 400 people were arrested during a weekend in which police armed with batons and tear gas fought running street battles with youths who threw stones and set fire to rubbish bins.
Six thousand police had been deployed on the streets of the capital to maintain order.
The family and friends of teenager Alexandros Grigoropoulos held a memorial service in the Exarchia district of Athens on Sunday evening to mark a year since his killing.
They appealed for calm, but posters had appeared in the capital saying: "We won't forget, we won't forgive."
Dozens of arrests
The heavy police presence in Athens prevented a repeat of Sunday's occupation of university buildings by masked protesters.
Christos Kittas, the dean of Athens University, was among 30 people injured on Sunday after youths broke into university offices, authorities said.
Dozens of shop windows were smashed, cars were damaged and on Monday morning the capital's Syntagma Square was left littered with rocks and piles of smouldering rubbish.
Police were forced to retreat on Sunday as protesters threw objects at them
But the protests have been nothing like the two weeks of riots sparked by the killing last year, says the BBC's Malcolm Brabant in Athens.
To head off trouble, riot police had carried out a series of raids on Saturday across Athens, reportedly arresting scores of people.
The demonstrations marked a dramatic change in police tactics, says our correspondent, as they employed a 21st Century version of the cavalry charge using riot police on motorbikes.
Greece's government had warned it would have a zero-tolerance policy towards violence, and has rejected allegations of heavy-handedness from left-wing groups.
Police said up to 150 foreign anarchists arrived over the weekend from Italy, France and other European countries.
Greek Prime Minister George Papandreou had acknowledged the weekend was a "crucial moment" for his new socialist government and for the nation.
Two police officers have been charged with the murder and attempted murder of 15-year-old Alexandros Grigoropoulos. Their trial is due to begin in the new year.
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