Athens was assessing the damage Sunday after a night of protests that degenerated into violence on the sixth anniversary of the police killing of a teenager.
A total of 296 people were detained during the night, a police source said, while 43 suspected of involvement in the rioting in the Greek capital were due to go before prosecutors.
Police used tear gas, stun grenades and water cannon as protesters, many of them masked, hurled rocks and Molotov cocktails.
The clashes broke out at the end of a rally to mark the anniversary of the shooting of 15-year-old Alexis Grigoropoulos by a policeman in 2008.
Protesters have organized marches each year to remember his death.
This year, an estimated 5,000 people turned out, according to police who mobilized a force of about 6,000, while organizers put the number of demonstrators at 10,000.
Twelve police officers were wounded in Saturday night's clashes in Athens, while incidents were also reported in other locations, including Greece's second city of Thessaloniki and the western city of Patras.
Athens deputy mayor Giorgos Apostolopoulos told local radio there had been «incalculable damage» at several sites in the city.
However, an AFP journalist reported that only limited damage was visible.
Bus shelters were vandalized along a main road, while damage including shattered windows was limited to a handful of streets around the Athens Polytechnic.
This year's remembrance day took on extra significance as marchers also rallied in support of Nikos Romanos, a 21-year-old jailed for attempted bank robbery.
Romanos, who has been accepted into a business degree programme, went on hunger strike last month after he was refused educational leave.
Romanos is known to many Greeks as the friend who was standing next to Grigoropoulos when he was shot during a row with two police officers. The incident plunged Greece into weeks of riots.