A European Union arrest warrant became possible after Sweden provided additional information on Högström’s place of birth, parents’ names and residence, court spokesman Rafal Lisak was quoted as saying by the Polish news agency PAP.

Such warrants aim to speed up the handover of suspects in the 27-nation European Union, smoothing often lengthy extradition procedures.

Polish justice authorities indicted Högström last month for his alleged involvement in the December 18 theft of the sign from the gate of the notorious camp set up in occupied Poland by Nazi Germany during World War II.

Högström, 34, a former neo-Nazi, has told Swedish media he was supposed to act as an intermediary to pick up the sign and sell it to a buyer, but in the end he wound up informing Polish police about the people behind the plot.

The sign was recovered by Polish police two days after the theft and five Polish men were arrested and charged.

The five-metre (16-foot) metal inscription — which means “Work Will Set You Free” in German — was returned by investigators to the Auschwitz museum on January 21.

But it was not back in place in time for last week’s commemoration of the 65th anniversary of Auschwitz’s liberation by Soviet troops on January 27, 1945, because the thieves had cut it into three pieces and it must be restored.

The Auschwitz museum put up a copy immediately after the theft.

The sign has long symbolised the horror of the camp where some 1.1 million people — one million of them Jews — fell victim to Nazi German genocide from 1940 to 1945.