Protesters clashed with police outside Greece’s parliament during a rally that drew tens of thousands of people Sunday against the Greek-Macedonia name deal.
At least 25 police officers were injured and seven people arrested, police said.
Demonstrators threw rocks, flares, firebombs, paint and other objects at riot police who responded with repeated volleys of tear gas.
Some protesters jumped over a fence and tried to scale the steps, but officers chased them back down.
One man draped in a Greek flag attacked police with a large stick, while others swung big flags on wooden poles and struck officers.