Nikolaos Michaloliakos was arrested along with twenty other party members including four MPs, amid widespread anger over the murder of anti-racist rapper Pavlos Fyssas, which has been traced back to the Golden Dawn party.
It is the first time a party leader and MPs have been arrested in Greece since the end of the military dictatorship in 1974.
Describing the move as an “extraordinary clampdown” by the Greek government, BBC News’s Athens correspondent Mark Lowen said:
“The government says it is [the murder of the rapper] that has definitively exposed a direct chain of command to the party leadership, providing the basis for Golden Dawn to be classified as a criminal group.
The party has already had the immunity provided for Greek MPs lifted and one of those arrested on Saturday was tried earlier in the year in a separate incident. But with these arrests and several suspensions of police officers accused of links to Golden Dawn, the government has done more against the party this week than in the past year.”