Thousands of Greeks have demonstrated in the western Athens suburb of Keratsini against the fatal stabbing of hip-hop artist and left-wing anti-fascist Pavlos Fyssas, known as Killah P, allegedly at the hands of a Golden Dawn "ideological sympathiser".

Clashes erupted between left-wing activists and riot police, with stones hurled and fires lit. Teargas and stun grenades were used to push protesters back, according to the BBC.

Police earlier raided Golden Dawn offices across the country, with street battles outside branches in Crete, Thessaloniki and Patra.

Officers blocked 6,000 demonstrators in Thessaloniki from marching on Golden Dawn's offices in the city. Angry protesters accused police of "protecting murderers."

Killah P, 34, was stabbed to death outside a cafeteria in Keratsini after an argument with the 45-year-old neo-Nazi activist. He and his group of friends were attacked by around 30 black-clad supporters of Golden Dawn.

The singer was allegedly stabbed several times by a man who appeared in a car after being called by members of the mob, according to eyewitnesses. The 45-year-old admitted being a member of Golden Dawn.

His wife, also held by police, attempted to throw away his Golden Dawn party card in a garbage bag outside the suspect's residence in Nikaia, south-eastern Attica.

The death of Killah P sparked a wave of anger and indignation across the country. There are calls for Greece's third-largest party - with 18 seats in the 300-member parliament - to be outlawed.

Minister of public order Nikos Dendias said the government will consider new laws on armed gangs, meaning the neo-Nazi party could be classified as a criminal group.

"Neither the state will tolerate, nor society accept, acts and practices that undermine the legal system," the minister told reporters.

Nikos Xydakis argued in Greek newspaper Ekathimerini that the country has hit its "Red Line" as far as Golden Dawn is concerned. "September 18, 2013, must be seen as a wake-up call for Greek democracy, the country's institutions and its citizens," he wrote.

The PanHellenic Socialist movement, which is part of the governing coalition, called for the party to be banned. Hannes Swoboda, president of the socialist group in the European parliament, called on Greece to consider banning the party:

"Golden Dawn's openly xenophobic, neo-Nazi hatred even goes as far as murdering political opponents. This is shocking and intolerable by any standards, and more so in a European Union country."

Greece president Karolos Papoulias said: "It is our duty not to allow any space whatsoever to fascism - not even an inch."

Earlier in 2013, the Council of Europe's commissioner for human rights Nils Muiznieks said that Greece would be "fully within its rights under international human rights law" to ban the party from public office.

However, he said that outlawing Golden Dawn would not be a panacea for Greece's far-right problem.

"If you ban Golden Dawn," he told AP, "you would still have the problem of racist violence in Greece which is the broader issue."

The party called the council of Europe a "Zionist instiution".