I have read in the papers that the Polish are worried nowadays.
Well, if the position according to the newspaper is correct (50 km southeast of Malmö) then I guess the Poles have reasons to worry.
A quick glance at the map says that this position would be about half way between Malmö and Sassnitz.
There are no international waters in the strict meaning of the expression in the Baltic Sea
afaik. There are only zones where "anything goes". The Baltic Sea is too small, there are no land that can have a standard sized economical zone without overlapping. Instead there are lots of treaties of varying degree of complicatedness...