Fifteen people were injured during clashes between self-styled anarchists and supporters of far-right Golden Dawn in the Athens neighbourhood of Aghios Panteleimonas late on Sunday.
According to police, a group of about 50 anarchists rode through Aghios Panteleimonas in a protest against the presence of Golden Dawn, which triggered the clashes.
Police said that local residents also clashed with the anarchists and that one of them brandished a gun during the scuffles but did not use it.
There were also clashes between Golden Dawn supporters and anarchists in Volos, central Greece, on Saturday.
The incident blew up after a confrontation involving the neofascist party?s local MP. A total of 11 people were detained.