Leader of the extreme far-right Golden Dawn party Nikos Michaloliakos is escorted by anti-terror police as he exits Greek Police headquarters, in Athens. (Angeliki Panagiotou/AP)

The leader of Greece’s extreme-right Golden Dawn party and four other of its lawmakers were formally charged Saturday with membership in a criminal organization with intent to commit crimes, in an escalation of a government crackdown after a fatal stabbing blamed on a supporter.

It was the first time since 1974 that sitting members of Parliament have been arrested. The arrests underline the Greek government’s efforts to stifle the fiercely anti-immigrant party, which has been increasingly on the defensive since the killing.

Golden Dawn leader Nikos Michaloliakos, party spokesman Ilias Kassidiaris and Yannis Lagos, Nikos Michos and Ilias Panayiotaros were arrested by counterterrorism police. The latter two gave themselves up voluntarily. A sixth lawmaker, Christos Pappas — described in a prosecutor’s report as the Golden Dawn’s No. 2 — remains at large.

An additional 15 people, including 13 Golden Dawn members and two police officers, have also been arrested and are due to appear before a prosecutor and an examining magistrate soon. They face the same charges.

A police official, speaking on the condition of anonymity because he wasn’t permitted to publicly reveal details of the ongoing operation, said that a total of 38 warrants had been issued and that the counterterrorism unit was searching for 18 suspects, including the missing deputy.

“It is an unprecedentedly dynamic response to a neo-Nazi organization,” government spokesman Simos Kedikoglou said, hinting that the arrests were the culmination of a long strategy to deal with Golden Dawn as a criminal, not a political force.

“The prime minister and the government were determined to deal with Golden Dawn solely through the justice system,” Kedikoglou said. “We have succeeded in stripping them of their political cover and dealing with them as what they really are, a criminal organization.”

The government ordered an investigation into Golden Dawn’s activities after the death of rapper Pavlos Fyssas on Sept. 18 sparked outrage across Greece. The suspect arrested in his death admitted to police that he had stabbed the 34-year-old and identified himself as a supporter of Golden Dawn. Police investigated his cellphone records and those of more than 300 people connected to Golden Dawn.

Investigations have extended to the police, who have been accused in the past of turning a blind eye to Golden Dawn violence and of mistreating immigrants.

Under existing anti-terrorism legislation, membership in a criminal organization is a crime for which the Golden Dawn deputies can be prosecuted without Parliament needing to lift their immunity.

Despite the arrests, the party’s lawmakers retain their legislative seats unless they are convicted of a crime. Golden Dawn holds 18 of Parliament’s 300 seats, after winning nearly 7 percent of the vote in general elections last year.

The party has vehemently denied any role in the killing, but it has appeared to dent Golden Dawn’s appeal among Greeks. As calls for a crackdown mounted, the party hinted that its lawmakers might resign to provoke elections in 15 multi-party constituencies.

“There will be no elections, certainly no general elections,” Kedikoglou said. Asked about the likelihood of partial elections if Golden Dawn deputies were to resign, he said “there are ways to deal with that, as well.”

“Justice, stability, no elections,” Prime Minister Antonis Samaras said as he hurried from his office to the Athens airport on his way to a six-day trip to the United States.

“Golden Dawn has indeed been losing ground at the polls since the man’s murder and I expect them to continue to lose ground,” Theodore Couloumbis, a political scientist and professor emeritus of International Relations at Athens University, said. “This is the beginning of the end for Golden Dawn.”

— Associated Press