Polish police Saturday stepped up border checks as they intensified the hunt for thieves who stole the infamous Nazi German "Arbeit macht frei" sign from the Auschwitz death camp.
Road blocks were in place across the southern Polish region, while around 40 officers and forensic experts were mobilised to gather evidence at the camp itself, said regional police spokesman Dariusz Nowak.
"This is an absolute priority for the Polish police," added national police spokeswoman, Grazyna Puchalska.
The sign, which means "Work Will Set You Free", came to symbolise the horror of the camp where 1.1 million mainly Jewish prisoners died during World War II, from overwork and starvation but mostly in the gas chambers.
Its theft Friday at dawn from the camp entrance sparked a chorus of outrage from world leaders, Jewish groups and Holocaust survivors.
Nowak said police had received dozen of telephone calls from residents around Oswiecim -- which was annexed and renamed Auschwitz by Germany during the war -- although none so far had enabled a breakthrough.
The Auschwitz museum has offered a reward of 100,000 zlotys (about 25,000 euros), and police 5,000-zlotys (1,200 euros/1,700-dollars), for any information leading to the recovery of the sign or arrests.
The five-metre (16-foot) long sign was forged by prisoners on the orders of the Nazis, who set up the camp after invading Poland in 1939.
It was later expanded into a vast death camp, after the Nazis razed the nearby village of Brzezinka -- Birkenau in German. The site has been a Polish state-run museum and memorial since the war ended in 1945.
Museum director Piotr Cywinski, contacted by AFP, admitted the museum has had to make do with a rudimentary surveillance system, since much of its limited budget has been channelled into urgent renovation work.
"The surveillance was concentrated on the archives and exhibited objects, because no sane person could have imagined such an act," he said.
"The camp entrance, from where the sign was stolen, was being monitored by just one camera, an old model. Moreover the snow meant the image was blurred," he added.
Last year the Auschwitz museum had a budget of 6.8 million euros, most of it provided by the Polish government to maintain the camp's 155 buildings and 300 ruins, and cater to more than a million annual visitors.
The museum launched an international appeal this year for 120 million euros for vital preservation work.
Source: AFP Global Edition