Golden Dawn leader Nikolaos Michaloliakos arrested

Link to video: Greeks agree with arrest of Golden Dawn leader Nikolaos Michaloliakos

Greek police have mounted an unprecedented crackdown on the neo-fascist Golden Dawn party, arresting its leader, three MPs, and more than a dozen other key members.

As the prime minister, Antonis Samaras, held emergency talks on Saturday with his public order and justice ministers, Nikos Michaloliakos, the extremist organisation's enigmatic founder, was being held by counter-terror officers after a carefully orchestrated operation that began in the early hours of the morning.

The arrested officials will appear in court over the weekend on charges of forming a criminal organization, police said.

Emerging from the talks with Samaras, the justice minister, Charalambos Athanasiou, said: "Justice has moved with decisiveness and transparency. I want to say for all those who have been arrested if they are sent to trial there will be just justice."

Authorities said some 25 counter-terrorism units were trying to track down two other MPs almost nine hours after Michaloliakos was arrested in his Athens home at 7am. Greek media quoted the politician as telling police "what you are doing is not right. The truth will shine," as he was taken away in handcuffs.

Hundreds of Golden Dawn supporters, many wearing the party's black T-shirts, gathered outside Athens' police headquarters, spurred on a text message reportedly sent by the party to "support our moral and just struggle against the corrupt system". Michaloliakos and his chief lieutenant, the party's spokesman Ilias Kasidiaris, were inside the building.

Yesterday Kasidiaris, who became infamous with an assault on two female leftwing MPs during a live television debate last year, joked that "we are here to hand ourselves in" as the party launched a lawsuit against Pasok, the junior leftist party in Samaras' fragile coaltion.

Police said weapons had been discovered in the crackdown. Three guns allegedly found in Michaloliakos' home were to undergo ballistics tests, the media reported.

Greece's third-biggest party, Golden Dawn has seen its popularity soar amid desperation and despair over the country's economy, becoming Europe's most extreme rightwing political force in the process. Human rights groups hold the party responsible for hundreds of attacks on dark-skinned immigrants in the three years since the debt-stricken country plunged into crisis.

Since being elected to parliament for the first time in June last year with 7% of the vote, Golden Dawn has been linked to a wave of violence directed mostly against migrants, gays and leftists on Greece's increasingly fractious political scene.

The fatal stabbing of Pavlos Fyssas, a hip hop star popular among anti-fascists earlier this month, prompted widespread outrage and finally galvanised the governing coalition into taking action. Amid revelations thatGolden Dawn had set up hit squads with the help of commandos in the special forces and openly colluded with the police, authorities launched a far-reaching inquiry into the group's activities. Two senior police generals resigned and several officers were suspended following allegations of links with the party. More than a dozen Golden Dawn members, including the 45-year-old man who confessed to murdering Fyssas, were rounded up.

It is the first time since 1974 that a party head and sitting MPs have been arrested. "This is without precedent in Greek political life," said professor of constitutional law Kostas Chrysogonos. "Authorities are acting within the law but I also think it would have been constitutionally more correct if they had asked parliament to lift their [MPs] political immunity first."

Even if the MPs are imprisoned pending trial, they will still retain their standing as deputies, experts say.

This week Kasidiaris told a TV show that "they can arrest us, they can put us in prison, but we will still be MPs. We are not going to go back even one step."

Although Samaras' shaky coalition has been applauded for its tough stance – with opinion polls showing a drop in support for Golden Dawn and a slight rise for his own conservative New Democracy party – there are fears that the crackdown could ultimately have a boomerang effect on the government.

The radical left main opposition leader, Alexis Tsipras, gave voice to those fears this week saying the party should be confronted "within the law, not outside it".

Before the crackdown Golden Dawn was polling at around 15%, prompting it to boast it had "more than a million" supporters nationwide.

Earlier this week, Michaloliakos warned he might withdraw his 18-strong parliamentary group from Greece's 300-seat parliament – a move that could unleash political instability in a country dependent on international rescue funds to survive.

The politician had also said that what he described as "mud-slinging and slander" against his party would also "open the gates of hell".