Seven people were arrested in the central Athens neighborhood of Exarchia early on Saturday after clashes with police. The trouble flared up at the end of a march to protest the visit to Athens of US Secretary of State John Kerry.
Police said that a group of around 100 people clashed with police just before midnight on Friday. The assailants threw Molotov cocktails and rocks at officers, authorities said.
A flare was also fired at police but it landed on the third-floor balcony of an apartment block, prompting a fire to break out. The fire service was called to put out the blaze.