Demonstrations are happening across Greece by anti-fascists groups following the killing of a left-wing activist by a suspected neo-Nazi.

A 45-year-old man has allegedly confessed to stabbing of left wing musician Pavlos Fyssas. The suspect is a supporter of far-right party Golden Dawn, which is blamed for a tide of attacks on immigrants.

Greece’s deputy PM said it must now be treated as a “criminal organisation”.

Evangelos Venizelos, who is the head of the Pasok socialist party, the junior party in the coalition government, said Golden Dawn had “violence as its priority”.

He and Prime Minister Antonis Samaras have agreed to use all available legal powers to crack down on the movement, Greek daily Kathimerini reports.

Golden Dawn has denied any connection with the killing and has turned on its accusers, calling them “miserable and wretched not only because of their brazen lies and slander but because they are exploiting a tragic event for politicking, to win votes and to divide Greek society”.