The main offices of Greece's extreme right Golden Dawn party have been attacked by a group of youths wielding sledgehammers.
Police say several people have been detained for questioning after the attack in Athens, which caused damage to the property. No-one was injured.
Youths smashed a shop front on the ground floor of the party headquarters on a busy road during rush hour traffic, and threw red paint at the entrance of the building.
Golden Dawn came third in the 2015 general elections, after a surge in popular support during the country's financial crisis.
Party offices have been targeted in the past in bomb attacks, while two Golden Dawn members were shot dead in 2013, an attack claimed by a far-left militant group.
Golden Dawn spokesman Ilias Kasidiaris accused the government of turning a blind eye to attacks against the party.
He added of the attack: "They think that with terrorism and petrol bombs, they will stop Golden Dawn.
"Golden Dawn will not be stopped, and it is the only force that is standing up to the selling out of Greece."