Poland’s Prime Minister Donald Tusk said on Wednesday that the NATO member intervened after detecting “suspicious” activity from a Russian “shadow fleet” ship near a cable in the Baltic Sea.
Security analysts say Russia is operating a large “shadow fleet” of hundreds of vessels, seeking to dodge the sanctions Western nations imposed on its oil exports over the war in Ukraine. 
Several undersea Baltic cables were damaged last year, with many experts calling it part of a “hybrid war” carried out by Russia against Western countries.
“A sanctioned Russian ship from the ‘shadow fleet’ was carrying out suspicious manoeuvres near a power cable connecting Poland to Sweden,” Tusk said on X.
“Following a successful intervention by our military, the vessel left for one of the Russian ports,” he added, saying a survey ship of the Polish navy was on its way to the site.
Polish Defence Minister Wladyslaw Kosiniak-Kamysz said the incident took place on Tuesday outside Polish waters.
“Tomorrow there will also be an emergency meeting at the Maritime Operations Command… with Prime Minister Tusk’s participation,” he told reporters.
The European Union on Tuesday adopted a new round of sanctions on Russia targeting its so-called shadow fleet, and threatened more punishment for Moscow for not agreeing a Ukraine truce.
The 17th package of sanctions includes blacklisting nearly 200 more tankers in Russia’s “shadow fleet” in a bid to curtail Moscow’s ability to export oil.
