Greek police fired tear gas to disperse protesting farmers after they tried to storm the Agriculture Ministry building in central Athens.
The clashes erupted when about 800 farmers from Crete - who came to Athens to demonstrate against the government's planned pension reforms - asked police to allow them to drive a pick-up truck with vegetables in front of the ministry as part of their protest and allow them entrance to the building.
When police turned down their demand, enraged farmers attacked them with shepherd's crooks and pelted them with vegetables. The scuffles quickly escalated and police fired rounds of tear gas to disperse the protesters who threw stones, smashed windows and set garbage bins on fire.
Four protesters were detained during the clashes, a police official said.