Five men detained over the theft of the metal sign that hung over the former Nazi death camp of Auschwitz acted from financial motives and were not members of a neo-Nazi group, Polish police said on Monday, hours after the sign was recovered.

The theft last Friday, triggered worldwide condemnation, especially from Israel and Jewish groups. Polish authorities made the recovery of the sign, which reads "Arbeit macht frei" ("Work makes you free"), a top priority.

"We can say that none of the five are members of a neo-Nazi group ... Their intent was undoubtedly robbery-related. We will be able to decide later whether the crime was ordered or whether they acted on their own initiative," Andrzej Rokita, district police chief in the city of Krakow, told a news conference.

The five detained men, whose ages ranged from 20 to 39, were detained early Monday and transferred to a police station in the southern city of Krakow.

Some 1.5 million people, mostly Jews, perished in the Nazi death camp located in southern Poland during World War Two. Prisoners arriving at the camp used to enter via a relatively small iron gate topped by the German-language motto.

More than 200 hectares (500 acres) of the former death camp became a museum after the war ended.

The wording of the sign became a symbol of the Nazis' efforts to deceive their victims into a false sense of security before murdering them.

Polish authorities made the recovery of the sign a priority and the museum, police and anonymous donors offered a reward of nearly $40,000 for information leading to its return.