Thieves have stolen gold, diamonds and cash thought to be worth millions of pounds from a German bank, leaving detectives baffled.

The mystery burglars escaped with the contents of over 200 safety deposit boxes at a branch of Deutsche Bank in the northern German city of Lübeck in a case that is reminiscent of the 2015 Hatton Garden heist.

Local media reported that the break-in was carried out on the weekend before Christmas, overnight from Dec 20 to 21.

Officers arrived shortly after the alarm went off inside the vault, but the burglars had already got away. It is understood that the alarm only sounded in the morning, after the thieves fled.

Officials said the value of the stolen goods is yet to be determined, but that it could easily reach into the millions.