BRUSSELS, Belgium: The well-preserved wreck of a German submarine sunk during World War I has been found in the North Sea and may have the bodies of its crew still on board, Belgian officials said Tuesday.

A diver who has explored the wreck, lying in 30 meters (100 feet) of water off the port of Ostend, said the good condition of the submarine suggested the remains of its 23 crew could still be inside.

It is the 11th German submarine from the 1914-18 war to be found in Belgian waters and the best-preserved example to date, Jan Mees, head of the Flanders Marine Institute told AFP.

The wreck was found in the summer by Thomas Termote, a diver and expert in marine archeology, but its exact location is being kept secret to deter treasure-hunters.

“The submarine is very intact, everything is still closed — that’s what he (Termote) saw during his first visit this summer,” Mees said.

The submarine would have had 22 crew and a commander on board, West Flanders provincial governor Carl Decaluwe told De Standaard newspaper.

“All the hatches are still closed. This suggests the wreck has not been discovered before and moreover the 23 crew members are still inside,” Decaluwe said.

During WWI, the German navy used the Belgian port of Zeebrugge as a base for its submarines, known as U-boats, to attack shipping in the North Sea.

To combat the U-boat threat, the British tried to block Zeebrugge port in April 1918 by scuttling old ships in the entry channel.