Greek police fired tear gas as farmers protesting against pension reforms tried to break into a government building ahead of a major demonstration.
Approximately 800 farmers from Crete scuffled with police guarding the Agriculture Ministry building in Athens.
Some threw stones breaking windows of the building as others pelted riot police with vegetables, bottles and bricks.
Other demonstrators hit riot police shields with their staffs as they tried to break through a cordon and set fire to bins.
"The farmers attempted to push the police in front of the ministry's entrance. The police used tear gas to stop them," a police official said.
Thousands of farmers across the country are expected to protest in the Greek capital against government plans to raise pension contributions and taxes.