Riots rage in Athens after peaceful march over teen's death

Protesters throw fireworks and flares at riot police during clashes in Athens, on Tuesday, Dec. 6, 2016. Riots have broken out in central Athens, with dozens of youths throwing petrol bombs at police after a peaceful march to commemorate the police killing of a teenager eight years ago. (AP Photo/Yorgos Karahalis) (The Associated Press)

Hooded youths use a lazer stick against riot police during clashes in Athens, on Tuesday, Dec. 6, 2016. Riots have broken out in central Athens, with dozens of youths throwing petrol bombs at police after a peaceful march to commemorate the police killing of a teenager eight years ago. (AP Photo/Yorgos Karahalis) (The Associated Press)

Protesters throw fireworks at riot police during clashes in Athens, on Tuesday, Dec. 6, 2016. Riots have broken out in central Athens, with dozens of youths throwing petrol bombs at police after a peaceful march to commemorate the police killing of a teenager eight years ago. (AP Photo/Yorgos Karahalis) (The Associated Press)

Riots raged for hours in central Athens Tuesday as dozens of anarchists threw petrol bombs, fireworks and stones at police after a peaceful march to commemorate the police killing of an unarmed teenager eight years ago.

Riot police used tear gas to contain young people who set up barricades around a university complex in the Exarcheia residential district, a traditional venue for protests that often turn violent.

Other rioters pelted police with the stones and petrol bombs from the roofs of surrounding apartment buildings. Police said one officer was hospitalized with light injuries, and at least 23 people were detained.

Young demonstrators also used petrol bombs and rocks to attack police during a separate clash in northern Greek city of Thessaloniki.

About 1,000 people had protested in the city center earlier Tuesday to mark the 2008 fatal shooting of 15-year-old Alexandros Grigoropoulos.

In Athens, about 1,500 anarchists and other demonstrators marched peacefully through the city to protest Grigoropoulos' killing by a police officer in the Exarcheia district, which sparked days of rioting in Greece's main cities.

Anarchists initiated violent clashes with police in Exarcheia last month, both during a visit by President Barack Obama and on the anniversary of a 1973 student uprising.