Thousands of people gathered outside the Greek parliament in Athens on Tuesday to protest against further proposed austerity measures.
Some scuffled with the police and tried to break down barriers.
A general strike has also shut public transport, schools and banks across Greece.
Leaders of the coalition parties in the government are under intense European pressure to sign off a new austerity package so Greece can qualify for bailout funds from the European Union and the International Monetary Fund.
The Greek economy has shrunk 12% since 2008.
On Monday, the government agreed to pass a new law allowing more civil service employees to be fired. The BBC reports that 15,000 jobs are likely to be cut.