The Grüne Gewölbe (or Green Vault) has been stripped of hundreds of artefacts, after the thieves reportedly started a fire in the early hours of Monday which led to a breakdown in the power supply and the failure of security alarms.

Police are calling the break-in the largest art heist in post-war history.

The Grüne Gewölbe’s most famous artefact is Augustus the Strong’s treasure chamber. It was not known whether it had been broken into.

A police spokesman said on Monday morning: “We can confirm that there has been a break-in in the Grüne Gewölbe… the perpetrators are on the run.”

Police were due to give a press conference at 1pm local time when more information about which items had been seized, was due to be released.

According to the tabloid Bild, the thieves appear to have targeted the jewellery collection in the gallery, entering the building via a small corner window.

Michael Kretschmer, the leader of Saxony, of which Dresden is the capital, said he was devastated by the losses. “Not only the gallery has been robbed, but also the Saxonians,” he said.

He was heading to the Grüne Gewölbe to assess the damage for himself, and did not know which treasures had been seized, he said. But he added: “The treasures one can find there, as well as in the Residence Palace, have been collected by the people of Saxony over many centuries and are hard-won treasures.

“You cannot understand the history of our country, or the free state of Saxony without the Grüne Gewölbe and the state art collections of Saxony”.

The Gewölbe alone consists of 10 rooms teeming with about 3,000 items of jewellery and other recognised masterpieces. The building was heavily damaged during the second world war, but has been successfully restored, reopening to great international fanfare in 2006. It has been a tourist magnet since 1724 when it first opened to the public.

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