(AP) Clashes have broken out between riot police and protesters holding an anti-fascist demonstration near the site of a fatal stabbing attributed to an extremist right-wing party.
Riot police fired tear gas and stun grenades Wednesday evening to disperse protesters, who local media said had attempted to attack the police station.
The demonstration was being held to protest the killing of Pavlos Fyssas, a 34-year-old musician who friends described as an anti-fascist activist.
Police say a 45-year-old man arrested for the attack has admitted to carrying out the stabbing and being a member of the far-right Golden Dawn party.
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Police raided the offices of Greece's far-right Golden Dawn party Wednesday after a man who identified himself as a party member was arrested in the fatal stabbing of a 34-year-old musician described as an anti-fascist activist.
While the party has often been blamed for numerous violent attacks in the past, the overnight stabbing is the most serious instance of violence directly attributed to a member of the extremist group so far.
Pavlos Fyssas, 34, died in a state hospital early Wednesday after being stabbed outside a cafe in the Keratsini area west of Athens. He suffered two stab wounds to the chest, authorities said.
A 45-year-old man arrested at the scene admitted to attacking Fyssas a hip-hop singer identified by friends as an anti-fascist campaigner and belonging to Golden Dawn, police said in a statement. A knife with traces of blood was found near his car.
The attack drew condemnation from across the political spectrum in Greece, and from abroad.
"Golden Dawn's openly xenophobic, neo-Nazi hatred even goes as far as murdering political opponents. This is shocking and intolerable by any standards, and more so in a European Union country," said Hannes Swoboda, an Austrian and president of the Socialists and Democrats Group in the European Parliament.
The suspect was to appear before a prosecutor later Wednesday. In Keratsini, hundreds of people gathered for an anti-fascist demonstration Wednesday evening, while similar protests were planned for the northern city of Thessaloniki.
At the scene, where blood still stained the sidewalk, friends of the victim and local residents left flowers and candles.
Golden Dawn, whose senior members have expressed admiration for Adolf Hitler although they deny being a neo-Nazi group, won nearly 7 percent of the vote in general elections last year. Recent opinion polls show its support has since risen to around 12 percent.
Party members and supporters, often clearly identifiable in black T-shirts and combat trousers, have been blamed for beatings and stabbings, usually of dark-skinned migrants, across the country.
In January, two men identified as party sympathizers were arrested for the fatal stabbing of a Pakistani migrant worker. But Wednesday's killing was the first attributed to a Golden Dawn member, and the most severe attributed to political rather than racial motives.
The party's deputies have also frequently engaged in outbursts and name-calling in Parliament, most recently insulting Muslim members of Parliament as Turkish agents.
"I am shaken by the event," Public Order Minister Nikos Dendias said of Wednesday's attack. The killing and recent violent incidents involving the party, along with name-calling in Parliament, "show in the clearest possible way the intentions of the neo-Nazi creation."
Five public prosecutors have been assigned to the case.
Golden Dawn, which denies it had any involvement in the stabbing, said party offices in the western city of Patras and on the island of Crete were attacked by groups of people wielding batons and throwing petrol bombs later in the day. It posted footage on its website showing riot police outside party offices.
Police spokesman Christos Parthenis said the suspect arrived during an altercation between two groups of people and stabbed Fyssas. Friends of the victim told Greek media they had been attacked by a large group of men as they left the cafe.
Golden Dawn spokesman Ilias Kasidiaris initially denied any party member or supporter had been involved, and described the stabbing as a "heinous crime." Later, party lawmaker Michalis Avranitis said the victim and the suspect had initially argued about a soccer match.
"Yes, this man, as it turns out, has declared himself to be a member of Golden Dawn. But Golden Dawn has 1 million supporters. If in a restaurant, two drunken idiots have a fight and someone is stabbed, should we look at their ideology and blame that?" Avranitis said in Parliament.
Government spokesman Simos Kedikoglou called "on all political forces to raise a barrier to the vicious cycle of tension and violence. Democracy needs stability, cohesion and responsibility from all."
Derek Gatopoulos in Athens contributed.