As the march that officials said drew 18,000 people in Athens was winding down yesterday, the 7,000-strong police contingent used tear gas and stun grenades to disperse a crowd burning American and European Union flags in front of the US embassy.
Some 14,000 demonstrators in Greece's second largest city Thessaloniki, who were watched over by 1,000 police, went home peacefully.
The march, which is a left and labour union tradition in Greece, commemorates the November 17, 1973 Athens Polytechnic university student uprising against the then ruling military dictatorship.
Each year the demonstrators march to the US embassy for a protest to denounce the role US intelligence agents played in the military dictatorship's rise to power.
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In recent years demonstrators have also used the anniversary to voice opposition to the harsh austerity measures imposed on Greece by its international creditors after the global financial crisis.
"At a moment when the government is trying to remove all sense of social justice through austerity measures, the demands of the Polytechnic remain current," the General Confederation of Greek Workers (GSEE), the country's main union, said in a statement.