Investigators have not officially established where or when the drone was launched, where it entered the sea or what mission it was carrying out.
According to the Operational Command’s spokesperson, Lt Col Jacek Goryszewski, the most likely explanation is that the drone drifted from international waters to Poland’s territorial waters.
The incident comes amid mounting tensions between Russia and European countries. On Tuesday, NATO jets shot down a drone that entered Lithuanian airspace, and a Russian frigate fired flares at a Danish military helicopter.
Poland’s Prime Minister Donald Tusk warned Sunday that “the coming weeks and months will be a period of very intense Russian activity,” adding that “the escalation of the Russian Federation’s actions is becoming a fact, and examples of this are getting closer and closer to our border.”