German customs authorities have detained a cargo ship that arrived from Russia at the German Baltic Sea port of Rostock because of suspicions about the ship’s contents, authorities announced on Tuesday. The ship, a 193-metre-long freighter, had arrived at the port on March 4 for repairs due to technical problems with its propeller, likely caused by voyaging through icy seas, German authorities said. But German customs officials pointed out that the ship’s cargo, like all goods brought into the European Union, was subject to customs supervision and inspection. German customs officials also cont…