Berlin — Robbers used a large drill to break into the vault of a German savings bank and stole about 30 million euros ($35 million) worth of cash, gold and jewelry, police said Tuesday.

Thieves broke into more than 3,000 safes in the heist in the western city of Gelsenkirchen, they said.

While the criminals remained at large, hundreds of agitated bank customers gathered in front of the branch on Tuesday, demanding information, but were kept at bay by the police.

According to the police, the robbers made their way from the garage to the Sparkasse savings bank’s underground vault.

Investigators suspect the gang spent most of the weekend inside, breaking into safety deposit boxes.

The break-in was discovered after the fire alarm went off in the early hours of Monday morning and emergency services discovered the hole.

Witnesses reported seeing several men carrying large bags on the stairs of the garage in the night from Saturday to Sunday.

The security camera footage shows a black Audi RS 6 leaving the garage early Monday morning, and there were masked people in it.

The car’s license plate was stolen earlier in the city of Hanover, police said.

A police spokesman told AFP the burglary was “really very professionally executed”, comparing it to the heist movie “Ocean’s Eleven”.

“There must have been a lot of prior knowledge and/or a lot of criminal energy involved to plan and execute this,” he said.

The police said that more than 3,000 boxes had an average insurance value of 10,000 euros, and therefore estimated the damage at around 30 million euros.

The robbery comes amid ongoing moves by the manager of one of Europe’s most famous museums, Paris’s Louvre, to yes strengthen insurance after a brazen heist in which thieves broke through an upstairs window to steal French crown jewels valued at $102 million. Four the suspected thieves were arrestedbut none of the state treasure was found.

Several robbery victims in Germany told police officers that their losses far exceeded the insured value of their safes.

A police spokesman said that “disgruntled customers” were outside the bank’s branch, which was closed for security reasons, after threats were made to employees.

“We are still on the scene, monitoring things,” he said, adding that “the situation has calmed down considerably.”