Russia said on Tuesday nothing suspicious was found on board the Arctic Sea ship, whose seizure by suspected pirates off the coast of Europe this month sparked a media storm, Reuters reported.
Media reports had speculated that the ship had a secret cargo of arms or even nuclear materials, saying a ship carrying timber in some of the world's best policed seas would be an unlikely target for pirates.
"The initial inspection of the ship did not uncover any suspicious cargo," Russia's Foreign Ministry said in a statement.
The Foreign Ministry said the captain initially said the ship was North Korean, but this information was denied by Pyongyang.
Russian prosecutors say the ship, which had a mainly Russian crew was operating with a Maltese flag when it was seized off the coast of Sweden.