ATHENS (AFP) - A major security operation took place in Athens on Friday to enable a prominent neo-Nazi politician jailed on crime charges to accept a seat on the city council.

Ilias Kassidiaris, spokesman of the neo-Nazi Golden Dawn party, was transported under heavy police guard from Korydallos prison to the swearing-in ceremony of the Athens city hall.

"We wanted to put the thieves in prison, but they beat us to it. It's okay, Greece always wins in the end," Kassidiaris told reporters on his way into the ceremony.

He took his oath and returned to prison.

Kassidiaris is in prison pending trial, accused of belonging to a criminal organisation. Magistrates accuse Golden Dawn of carrying out attacks on migrants and political opponents that caused at least two deaths.

Golden Dawn says the prosecutions are politically motivated to stem its rise.

Overall, nine Golden Dawn lawmakers including its leader Nikos Michaloliakos are behind bars, with trial proceedings expected to begin in the autumn.

Other party members are under house arrest.

Temporary release was granted to Kassidiaris and another two lawmakers elected to council posts in local elections in May to attend their investitures this week.

Anti-racist groups have staged protests at swearing-in ceremonies attended by Golden Dawn councillors.

Founded in the 1980s, the openly xenophobic and anti-Semitic Golden Dawn was for years a semi-clandestine group on the fringes of Greek politics.

But in 2012 the party won 18 seats in parliament, tapping into widespread anger over immigration and austerity reforms in the debt-ridden country.

While two of its MPs have since resigned from the party, Golden Dawn also came third in May's European elections, winning three seats.