Published on Wednesday, 08 August 2012 23:58 Written by EuroNews
The Golden Dawn activists ran onto a ferry near Athens, as the vehicle carrying the 21-year-old suspect left the ship.
The man is accused of attempting to kill a 15-year-old Greek girl on the island of Paros and was being transported to a mainland prison.
It comes after Greek police said they were deporting hundreds of illegal immigrants, after a major crackdown in Athens. Dozens of people were sent back to Pakistan at the weekend.
Golden Dawn, described by opponents as neo-Nazis, won enough votes in a recent election to enter parliament.