The sign, which cynically states "Arbeit Macht Frei," German for "Work will set you free," was stolen earlier Friday

Foreign Ministry official Yossi Levy said that Israel was "astounded and angry about the theft at Auschwitz."

"Israel has full faith in the Polish authorities in charge of the investigation, and believe that the Polish police will apprehend the inhuman thieves and restore the sign to its place to serve as a chilling testimony of the horrors committed at the camp."

Polish police spokeswoman Katarzyna Padlo said local authorities believed the sign was stolen between 3:30 a.m. and 5 a.m., when museum guards noticed that it was missing and alerted the police.

Padlo added that the iron sign, which spanned a gate at the main entrance to the former Nazi death camp, was removed by being unscrewed on one side and pulled off on the other.

The daily Gazeta Wyborcza said on its website that the museum authorities had already installed a replica sign over the gate that had been used briefly a few years ago when the original was being repaired.

"This [theft] is very saddening," Gazeta Wyborcza quoted Jaroslaw Mensfelt, the museum's spokesman, as saying.

"The thieves either didn't know where they were or -- what's even worse -- they did know but that didn't prevent them from stealing."

Information and Diaspora Minister Yuli Edelstein said in response that "this is one the Polish police's biggest failures," adding that" anti-Semitic events in the world are multiplying, and there is a valid fear for the safety of the Jews in the Diaspora."

Noah Flug, who heads an umbrella organization of Holocaust survivors' advocacy groups in Israel, said that he hopes the Polish police direct major efforts towards solving the crime and bringing the perpetrators to justice.

Hundreds of thousands of people 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.

On Wednesday, Germany committed itself to paying half the cost of restoring the leaky buildings and crumbling personal possessions of the former Nazi death camp.

The premiers of Germany's 16 federal states and Chancellor Angela Merkel agreed in Berlin to contribute 60 million euros, saying Auschwitz must be maintained as a monument to condemn the Holocaust and Nazi reign of terror.

Over 1 million people, the large majority of whom were Jews, were murdered at the Auschwitz-Birkenau extermination camp, spread over three sites. Birkenau, also known as Auschwitz II, was the site of gas chambers.

The Auschwitz-Birkenau International Memorial Foundation has appealed for 120 million euros to patch up 150 buildings and the ruins of 300 others. The money is also needed to preserve victims' stored personal effects, including 80,000 shoes and 3,800 suitcases.