Greek riot police have fired tear gas and fought running battles with protesters, amid a 48-hour general strike that has paralysed the country.
Some protesters hurled petrol bombs and stones at the police, as a march by tens of thousands of people in central Athens turned violent.
Many Greeks are furious at the latest round of austerity proposals.
EU leaders and global finance chiefs have flown to Germany to discuss the eurozone crisis.
French President Nicolas Sarkozy will meet German Chancellor Angela Merkel and senior officials from the European Central Bank and IMF.
Greece is struggling to reduce a huge government deficit amid fears it may default and set off a crisis, engulfing other eurozone countries like Spain and Italy.
The EU and IMF have demanded tough cuts in return for two bailout packages, and their meeting in Frankfurt comes days before high-level EU talks on the crisis. (BBC)
