The man is one of the people who have been identified as responsible for the explosions in the Baltic Sea three years ago.
Previously, another Ukrainian has been arrested in Italy. Recently, a court decided that he will be extradited to Germany.
The bombings of the gas pipelines have been investigated by several countries, including Sweden, but it is Germany that handles the legal aftermath.
The actions are believed to have links to the war in Ukraine, and suspicions have at various stages been directed against both Russia and Ukraine.
