KRAKOW, Poland (Reuters) - Polish police detained five men on Monday for stealing the metal sign that hung over the former Nazi death camp Auschwitz, and said they were common thieves, not neo-Nazis. Last Friday's theft triggered widespread outrage, especially from Israel and Jewish groups, amid fears of a political motive. The sign, which carries the German motto "Arbeit macht frei" ("Work makes you free"), is a powerful symbol of the Holocaust committed by the Nazis against the Jews. The police said it had been cut into three pieces.

"None of the five suspects is a member of a neo-Nazi group," said Andrzej Rokita, district police chief in the southern Polish city of Krakow, which is near the site of Auschwitz.

"Their motive was undoubtedly theft. We'll be able to say later whether the crime was ordered or they acted on their own initiative," he told a news conference.

Police said the suspects, aged between 20 and 39, had previous convictions for various crimes including robbery and physical assault. One of them ran his own construction firm.

Authorities had made recovering the sign a national priority and the museum that runs Auschwitz offered a reward worth nearly $40,000. Police said they had received more than 100 calls offering information.

Some 1.5 million people, mostly Jews, perished at the death camp during Nazi Germany's occupation of Poland in World War Two. Arriving prisoners used to enter via a small iron gate topped by the sign.

"ASSAULT ON HISTORY"

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

Jewish groups welcomed the news the sign had been recovered.

"The theft of the symbol of Auschwitz was not merely an act of vandalism. It was a crime against mankind and memory," the American Gathering of Holocaust Survivors and their Descendants said in a statement.

"Punishment should be swiftly meted out to those involved in this assault on history."

Welcoming the recovery of the sign, Jerusalem's Holocaust remembrance center, Yad Vashem, highlighted need for education.

"We must continue to work toward meaningful Holocaust education, so that the symbols of the Holocaust will be infused with meaning that will help build a better future, and can serve as catalyst in the fight against anti-Semitism and racism," Chairman Avner Shalev said in a statement.

Israeli President Shimon Peres had personally appealed to the Polish government to recover the sign.

One Polish lawmaker from Prime Minister Donald Tusk's center-right Civic Platform, Jaroslaw Gowin, said over the weekend he feared the theft had been meant to disgrace Poland internationally.

Museum authorities said the gate from which the sign was removed was not directly monitored by closed-circuit cameras.

The motto became a symbol of the Nazis' efforts to give their victims a false sense of security before murdering them.

Auschwitz prisoners died of diseases, sub-zero temperatures, starvation and in medical experiments as well as being gassed.

Hundreds of thousands visit the museum every year, but ticket sales are not enough to maintain the open-air site with its 155 buildings -- including the gas chambers -- 300 ruined facilities and hundreds of thousands of personal items.

Poland has appealed for international donations and Britain and Germany, among others, have offered money.

In January, Poland marks the 65th anniversary of the camp's liberation by the Soviet Red Army.

(Additional reporting by Chris Borowski in Warsaw and Ori Lewis in Jerusalem, writing by Gareth Jones, editing by Robin Pomeroy)