Rampaging protesters yesterday threw petrol bombs at police and set shops on fire as a march in Athens to commemorate the anniversary of the police killing of a teenager turned violent. Riot police used teargas and water cannon to beat back protesters in the bohemian Exarchia neighborhood, where about 200 black-clad youths hurled stones and Molotov cocktails at them. A cloud of smoke billowed into the sky from the clashes. At least two shops were set on fire, and dozens of others damaged. Police said they detained nearly 100 demonstrators. A riot police officer runs away from a protester's petrol bomb as it explodes perilously close to him during riots in Athens Masked protesters attempt to set a riot police truck on fire using home made petrol bombs The clashes erupted after about 6,000 protesters marched to commemorate the 2008 police shooting of Alexandros Grigoropoulos - a killing that led to two weeks of the most violent rioting Greece had seen in decades. This year's protest was in solidarity with a jailed self-proclaimed anarchist who witnessed the death of Grigoropoulos and who is now on hunger strike demanding he be allowed to attend university classes Nikos Romanos, 21, was sentenced to prison for robbery in October and began his hunger strike on November 10. He is in critical condition in hospital.