An intact German First World War submarine containing the bodies of 23 people has been found off the coast of Belgium, authorities said Tuesday.

Western Flanders Governor Carl Decaluwe told the Associated Press that the find on the floor of the North Sea “is very unique.”

“It’s quite amazing that we found something like this,” Decaluwe said. “The impact damage was at the front, but the submarine remains closed and there are 23 people still onboard.”

The UB II-type dive boat that was found is 27 metres (88 feet) long and 6 metres (almost 20 feet) wide, and is lying at about a 45 degree angle, between 25-30 metres (82-98 feet) below the surface.

From the damage to the front of the vessel, it appears that the sub may have struck a mine with its upper deck. Two torpedo tubes have been destroyed but the lower tube is intact and closed.

Video images show the submarine encrusted with barnacles and seaweed. It is also adorned with fishing gear, including nets.

Decaluwe said the U-boat was found by researchers. He declined to provide details about its location until the site has been protected. He has contacted the German ambassador because “we need to see what can do” with the remains.

Around 18 U-boats were stationed with the Flanders Flotilla in Bruges between 1915 and 1918. Thirteen of them were destroyed.

The killing fields of the First World War Show all 17 1 /17 The killing fields of the First World War The killing fields of the First World War Tyne Cot cemetery in a Flanders field near Ypres: most of the soldiers buried here are British Stefan Boness/Panos Pictures The killing fields of the First World War A recently discovered bunker in a Flanders field near Kemmel, Belgium Stefan Boness/Panos Pictures The killing fields of the First World War The landscape of Mesen near Ypres Stefan Boness/Panos Pictures The killing fields of the First World War Gravestones in a snow-covered Flanders field cemetery in Langemark Stefan Boness/Panos Pictures The killing fields of the First World War Old munition shells at Hill 62 Stefan Boness/Panos Pictures The killing fields of the First World War The Hill 60 crater was formed on 7 June 1917, when British miners and soldiers dug a tunnel under the German front post and detonated 45,000 kilos of explosives Stefan Boness/Panos Pictures The killing fields of the First World War A bunker at Langemark Stefan Boness/Panos Pictures The killing fields of the First World War Crosses with poppies in memory of the fallen soldiers at Hill 62 Stefan Boness/Panos Pictures The killing fields of the First World War The names of German soldiers at a war cemetery near Ypres Stefan Boness/Panos Pictures The killing fields of the First World War The A19 motorway cuts through Flanders fields Stefan Boness/Panos Pictures The killing fields of the First World War Signs for Ypres, Passchendaele and Langemark Stefan Boness/Panos Pictures The killing fields of the First World War A former battlefield near Wieltje Stefan Boness/Panos Pictures The killing fields of the First World War A golf course next to the Oak Dump cemetery Stefan Boness/Panos Pictures The killing fields of the First World War An Irish memorial cuts through a Flanders field near Mesen; Zandvoorde Stefan Boness/Panos Pictures The killing fields of the First World War A German bunker near Ypres Stefan Boness/Panos Pictures The killing fields of the First World War Trees along the N313 near Admiral's Road Stefan Boness/Panos Pictures The killing fields of the First World War A shrine at Totenmuehle Stefan Boness/Panos Pictures

It’s the 11th such wreck to be found in Belgian waters.

Allied warships and cargo ships were easy pickings for the German subs that were launched from Bruges, just across the English Channel.