Greek police fired teargas and used a water cannon to disperse protesters who hurled petrol bombs at police and set alight bank ATMs and garbage cans in central Athens on Saturday, police said.
At least 20 people have been detained.A march through central Athens to mark the sixth anniversary of the fatal police shooting of an unarmed teenager quickly turned violent Saturday, as marchers damaged store fronts and bus stations, and set fire to clothes looted from a shop.
Clashes also broke out between police and demonstrators marching through the northern city of Thessaloniki. At night, police fired tear gas and stun grenades after a crowd of marchers beat up two plainclothes policemen there.
No casualties were immediately reported in either city.
The marches are commemorating the Dec. 6, 2008, police killing of 15-year-old Alexandros Grigoropoulos in the capital, which led to two weeks of the most violent rioting Greece had seen in decades.
On Saturday, about 5,000 people were marching in Athens, passing the Greek Parliament and heading toward the spot where Grigoropoulos was killed, police said. At one point during, people broke into a Zara clothes shop, took racks of clothes into the street and burned them.
Clashes took in the Athens neighborhood of Exarchia, a haven for extreme leftists and anarchists, where Grigoropoulos was killed. Police cordoned off the neighborhood's central square, firing tear gas and pepper spray. Police also had two vehicles armed with water cannons.
The marches come at a time when nearly nightly violent protests are being held by supporters of one of Grigoropoulos' friends, jailed anarchist and convicted bank robber Nikos Romanos, 21. He was present when Grigoropoulos was killed and is now on a hunger strike, demanding prison leave to attend lectures after he passed university entrance exams.
Romanos, currently hospitalized under police guard, has been on the hunger strike since last month and doctors have said his health is failing. He was jailed with three young men following a February 2013 bank robbery in which they took a hostage as they tried to escape. Police released doctored mug shots of the four at the time to remove signs of severe facial bruising caused during their arrests, leading to an outcry at the time.
Prime Minister Antonis Samaras will meet with Romanos' parents on Monday morning, following a request made through their lawyer on Saturday, the government said.