Trade union group protesters have clashed with riot police in Athens over the Greek government's austerity measures and public spending cuts.
Tear gas and petrol bombs have been used in the violence.
For the first time last week, an outpouring of public anger succeeded in forcing a European leader to back down on austerity plans.
Greek riot police fired tear gas at hooded protesters hurling petrol bombs and stones as tens of thousands took to the streets.
Greece has suffered long, hot summer in which the downward spiral into debt-deflation has continued, possibly even accelerated.