Riot police fired tear gas to disperse a crowd of angry protesters as tens of thousands of striking workers marched through central Athens on Tuesday to protest against a new round of painful austerity measures, DPA reported.
More than 5,000 police were stationed across the city center as 15,000 people marched to parliament in two separate demonstrations.
Another 10,000 protesters marched in the northern port city of Thessaloniki.
The protests come as Greeks began a 48-hour strike ahead of a vote by parliament on a proposed austerity package of 28 billion euros (41 billion dollars) in spending cuts and tax hikes by 2015 to secure continued funding from a 110-billion-euro international bailout package.