A 66-foot submarine with reported Russian script on the side was discovered by a private company off the coast of Sweden.
Discovered by the company, Ocean X, Swedish authorities are investigating video recorded by Ocean X to determine the submarine's origin. It's unclear how long the submarine has been there and old it is.
A diver for Ocean X, Stefan Hogeborn, told Reuter the hull remains "intact" and the hatches remain "closed."
A submarine expert told Expressen, a Swedish tabloid, he believed the submarine was a Russian "Catfish" which were built in the early 20th century.
Ocean X officials said they will send a team to investigate the wreck further.
Russian aggression in Ukraine and sightings of Russian submarines across the North Sea and Arctic Ocean have worried Scandinavian countries such as Sweden and Norway.
-- Michael Hoffman can be reached at Mike.Hoffman@military.com