ATHENS, Greece -- Moving to drain power from one of the most violent rightist organizations in Europe, the Greek government conducted an extraordinary crackdown on the neo-fascist Golden Dawn party Saturday, arresting five members of Parliament, including the leader of the group, and at least 15 other people.
A search was underway for another lawmaker and at least 10 more party members.
It is the first time that the leader of a political party and members of Parliament have been arrested in Greece since the fall of a military junta in 1974.
Less than two weeks ago, the murder of an anti-fascist Greek singer ignited an uproar throughout Greece after the suspect claimed to be a supporter of Golden Dawn.
Since 2012, when it gained seats in Parliament, Golden Dawn has engaged in a campaign of intimidation against immigrants, but reports linking its name and ideology to the death of a native Greek have generated a wider backlash against it. The killing, and the public outcry over it, put substantial pressure on the government to move ahead with an investigation of the party.
On Saturday, Nikos Michaloliakos, Golden Dawn's leader and a member of Parliament, was taken into custody on charges of forming a criminal organization. The other arrests followed.
The police have not yet released details of the criminal charges, but they include murder, attempted murder and blackmail, according to a court official.
The move is likely to curb Golden Dawn's influence, at least for now, especially in Parliament, where the party holds 18 seats after elections last year during a volatile moment when Greece was on the precipice of exiting the 17-member eurozone.
Nonetheless, the disenchantment stoked by the economic crisis that helped propel Golden Dawn's rise is unlikely to fade anytime soon.
"As the country is mired in its worst economic crisis in modern history, support for extremist and anti-establishment parties is likely to remain high in the coming years, regardless of the future of Golden Dawn as a political party," Mr. Stratfor, a geopolitical intelligence, economic and political firm, said in an analysis.
Human rights groups say Golden Dawn, whose members perform Nazi salutes at rallies and meetings, has systematically terrorized immigrants, while the police have looked the other way. The aggressive acts include the beating of immigrants with clubs and shields bearing swastikalike symbols or with wooden poles draped in the Greek flag.
The sweep Saturday caught the top leadership of Golden Dawn, which was established in 1987 but whose influence has grown in tandem with the country's devastating economic hardship. Offering promises to restore jobs and order, the party's members also espouse nationalistic and xenophobic stances, appealing to marginalized Greeks in rough areas populated by a rising number of unemployed immigrants, mostly from Pakistan and North Africa.
The immunity usually enjoyed by Greek members of Parliament is automatically lifted in the case of felonies. For lesser charges, a vote must be held in Parliament.
In addition, two police officers connected with the organization were caught up in the sweep, a sign that a parallel crackdown is intensifying against parts of the Greek police force long thought to have been infiltrated by members or sympathizers of the group.
The party also had links to organized crime groups, particularly in Korydallos, southwest of Athens, close to the spot where the leftist rapper Pavlos Fyssas, 34, was killed last week. The police say a Golden Dawn supporter confessed to stabbing Fyssas.
"It's a big deal that the chief of the political party got arrested; most people are glad that something was finally done," said Aris Papaspyrou, 32, an Athens-based lawyer.
"But I'm not sure this will be the end, because we've seen in history something like this happen with Hitler and Nazi Germany," Mr. Papaspyrou added. "They took him to jail, but when he came out he created the party that won the election and went on to become prime minister. I hope this will not come back as a boomerang for us."