Athens (CNN) -- The leader of Greece's extreme right wing Golden Dawn party and four party lawmakers have been arrested on charges of forming a criminal gang, Athens police said Saturday.
The arrests of the leader, Nikos Michaloliakos, and lawmakers Elias Kassidiaris, Elias Panagiotaros, Ioannis Lagos and Nikos Mihos are part of a crackdown following a controversial stabbing death.
At least 10 more people have been arrested, including Golden Dawn party members, police said. More than 30 warrants were issued as police operations were launched across Greece Saturday.
One more Golden Dawn lawmaker is still being sought, police said.
Pavlos Fyssas, a popular anti-fascist figure and well-known hip-hop artist with the stage name Killah P, was the victim of the knife attack that was allegedly committed by a Golden Dawn supporter.
Clashes broke out in a working-class Athens suburb last week, as Fyssas' death inflamed already growing concerns about the rising influence of Golden Dawn. The ultranationalist, anti-immigration party has been linked by critics to street violence and neo-Nazism.
The violence came despite police raids of Golden Dawn offices and the arrest of a 45-year-old party supporter who police say admitted killing Pavlos Fyssas.
Kassidiaris last week denied his party's involvement in Fyssas' death, calling it a "heinous crime."
The singer's death has nevertheless led to renewed calls to ban Golden Dawn
The Greek constitution does not allow for political parties to be banned, however, and the party's arrested lawmakers will retain their parliamentary seats unless they are convicted of a crime.
Golden Dawn holds 18 of Parliament's 300 seats.
It is the first time since the restoration of democracy in 1974, following a seven-year junta, that a party leader and members of parliament have been arrested.
Deputy Prime Minister Evangelos Venizelos, whose socialist Pasok party is part of the governing coalition, said last week that Golden Dawn "must be dealt with as a criminal organization."
In 2012, the party rode a wave of dissatisfaction among some Greeks over internationally imposed austerity measures amid the country's deep financial crisis, winning 7% of the vote and gaining seats in parliament for the first time.
Recent polls had seen support rise as high as 12%. However, since Fyssas' killing last week, opinion polls suggest that Golden Dawn's popularity has dropped.
A poll carried out from September 19 to 21 by Rass, for the Eleftheros Typos newspaper, indicated that support for Golden Dawn had fallen to 5.8%, down from 8.3% on September 15.
Back in 2009, before the financial crisis and ensuing austerity measures hit Greeks hard, the party polled only 0.3%.