It would be hard to find a reason. It's the Baltic Sea. Maybe Germany was feeling its oats and thought to ask "May I see your papers?" The Sea is so narrow, I'm not sure there is really any international water there. If it really was headed to Russia, and the Germans interdicted it, that would be an embargo, which is an act of war.
I hope and expect this will blow over. If it gets to the stage of an embargo, Russia would doubtless protest. Then the Germans would let it go. Then the tanker could be mysteriously torpedoed, and an international incident would result.
It would be hard to find a reason. It's the Baltic Sea. Maybe Germany was feeling its oats and thought to ask "May I see your papers?" The Sea is so narrow, I'm not sure there is really any international water there. If it really was headed to Russia, and the Germans interdicted it, that would be an embargo, which is an act of war.
I hope and expect this will blow over. If it gets to the stage of an embargo, Russia would doubtless protest. Then the Germans would let it go. Then the tanker could be mysteriously torpedoed, and an international incident would result.
120 miles average. Pretty sure there's plenty of international waters.
It is territorial water from Norway-Denmark to Sweden-Poland. https://os.copernicus.org/articles/17/699/2021/os-17-699-2021-f02-web.png
3 miles from shore, it's international.
12 miles is the limit https://os.copernicus.org/articles/17/699/2021/os-17-699-2021-f02-web.png