Greece's far-right Golden Dawn party's offices in Athens have been firebombed in the wake of a suspected racist murder of a young Iraqi man in the city.
The offices on the fourth floor of a building in the central Pangrati area were empty at the time of the attack and nobody was hurt. The arsonists escaped.
Golden Dawn said: "It is yet another terrorist attack. The national struggle will continue just as powerfully until Greece belongs once more to the Greeks."
Council of Europe Commissioner for Human Rights Nils Muiznieks has urged the government to probe the legality of the party. He called it the "most overtly extremist and Nazi party in Europe".
The party, which first gained notoriety in 1991 by attacking Albanian immigrants and participating in the massacre of Muslims in Bosnia, has seen a steady rise in support as Greece's economic crisis rumbles on. Its share of the vote has jumped from 0.46 to 7 percent in three years.
Members were suspected of the murder of a 19-year-old Iraqi man who was stabbed in Athens by five men on motorbikes.
He died in hospital of injuries sustained from a sharp object. Police said the assailants had earlier tried to attack a Romanian and a Moroccan in the same area.
The murder comes during a nationwide campaign of migrant expulsions, organised by the government, and follows a violent assault by party members on a police vehicle carrying a Pakistani murder suspect.