Up to 80,000 Greeks flooded into Syntagma Square in Athens today ahead of a crucial vote on the latest austerity measures to blight the country.
Hundreds of riot police were deployed outside Parliament as protesters called for MPs to reject €13.5 billion (£10.8bn) of cuts demanded by the EU, International Monetary Fund and European Central Bank.
Opposition leftist party Syriza demanded a vote on the constitutionality of the austerity measures.
Parts of the measures have been ruled unconstitutional by the Supreme Court but MPs decided they were allowed by 170 votes to 47 - Syriza refused to take part in the vote.
Conservative Prime Minister Antonis Samaras's coalition government only controls 176-seats in the 300-member parliament and last night's vote was expected to be close as junior partner Democratic Left had already said its 16 MPs would vote against the measures.
With a series of defections and promises of more from Socialist Party coalition partners the paper-thin majority was likely to be further eroded.
Aside from the seething protesters, Athens was at a near standstill as the country's 48-hour general strike rolled into its second day.
And transport unions will pledg to continue their walkout tomorrow if austerity measures continue.
Earlier in the day Greek municipal workers briefly occupied the Administrative Reform ministry and about 40 uniformed police officers demonstrated outside parliament.
Unions have also called for a major demonstration outside parliament on Sunday when the 2013 budget will be voted on.