Greek police come under fire during an Athens protest marking the police killing of a teenage student hree years ago.

Story highlights

Student protesters mark the fatal shooting of a teenager by police three years ago

Activists clash with riot police in a central square

A larger protest is expected later by anti-establishment groups

Athens, Greece CNN  — 

Riot police and protesters clashed Tuesday in central Athens as a student rally was held to mark the third anniversary of the fatal shooting of a teenager by police.

Video showed activists throwing stones and Molotov cocktails at riot police, while clouds of what appeared to be tear gas drifted across the square.

When Alexis Grigoropoulos, 15, was shot and killed by a police officer in December 2008, his death sparked the worst riots the country had seen in years.

The officer responsible, Epaminondas Korkoneas, was found guilty of culpable homicide in October last year.

Anti-establishment groups are expected to stage a second, larger protest later Tuesday, as public anger simmers over Greece’s continuing debt crisis.

More than 7,000 police officers have been deployed and the city center will remain cordoned off, Athens police said.