Scuffles have broken out in Athens, as thousands of people demonstrated during an annual student rally.
Outside parliament, masked youths hurled homemade petrol bombs at riot police, who retaliated with tear gas and stun grenades.
Some 60 people were detained but no injuries were reported.
According to police estimates, some 28,000 people took part in the march, which comes amid unpopular austerity measures.
New Prime Minister Lucas Papademos has said his priority would be ratifying a 130 billion-euro bailout package agreed with the European Union to prevent Greece from defaulting on its massive debt.
compiled from agency reports