German investigators are examining possible links between unidentified drones spotted over northern Germany and a Russian "shadow fleet" vessel, Spiegel reported on Oct. 2, citing security sources. The "shadow fleet" refers to vessels with opaque ownership structures that use flags of convenience to evade Western sanctions and oversight. The Ukrainian president urged Europe to deny Russian tankers access to the Baltic Sea, calling the activity "de facto Russia's military activity against European countries." In early September, Russian drones were shot down over Poland. The same week, drones also entered Romanian airspace, though Bucharest opted not to intercept them.