Police fired tear gas today when rival far-right and anarchist demonstrators clashed in central Athens, sending shoppers rushing into stores for safety.
A scheduled march by about 60 members of Greece's far-right Golden Dawn group was met by anarchists, leading to a series of skirmishes that spread through the city's back streets.
"About 400 anarchists barricaded themselves along the main street throwing rocks and petrol bombs," a police officer at the scene said. "Two policemen and two anarchists have been slightly hurt, but there are no serious injuries."
Police cordoned off the city centre as the groups clashed and lit fires, causing huge traffic jams.
Golden Dawn, an extreme right-wing group with links to European neo-Nazis, was commemorating the date in 1996 when Greece and Turkey almost went to war over an uninhabited island in the Aegean known as Imia in Greek and Kardak in Turkish.
"The situation has calmed down, but we are still on alert for any escalation," the police officer said.