Students hurled rocks and bottles during clashes with police at a rally to mark the third anniversary of the fatal police shooting of a teenager in central Athens.
About 2,000 youths threw rocks, bottles, paving stones and oranges at police outside Parliament and smashed two nearby store fronts and three bus stops.
Another group of teenagers attacked two suburban police stations with rocks and bottles.
Police dispersed the youths with a small amount of tear gas after the protesters used at least two fire bombs.
Police reported 14 officers were injured; nine people were arrested and six detained.
The shooting death of 15-year-old Alexis Grigoropoulos on Dec. 6, 2008 sparked two weeks of the worst rioting the country has seen in decades.
Some 5,000 police were on duty in the capital for Tuesday’s rallies, set to continue throughout the day.
Violence was also reported in Greece’s second-largest city, Thessaloniki, where police detained two people after a crowd of youths threw rocks at a government building.
Last year, a court sentenced a police officer to life in prison for Grigoropoulos’ death, and a second officer to 10 years.