Swedish divers July 27 said they have found the wreck of a Russian mini-submarine in Swedish territorial waters.
The discovery comes a year after Swedish troops unsuccessfully hunted for a Russian submarine reportedly sighted near Stockholm, in the country's biggest military mobilization since the Cold War.
The Swedish military reacted with caution to the discovery.
"Our analysts have not yet presented their conclusions and want to see more images," said Swedish Armed Forces spokesman Anders Kallin.
Stefan Hogeborn, a diver from the Ocean X Team company that made the discovery, said the vessel is "completely intact" with "no visible damage to the hull" and the hatches closed.
"It is unclear how old the submarine is and how long it has been laying at the sea floor, but the Cyrillic letters on the hull indicate that it is Russian," he said.
Expressen tabloid, which published images of the wreck on its website, said it was found 1.5 nautical miles off the east coast of central Sweden.
Ocean X said the vessel was around 20 meters long and 3.5 meters wide.