Poland said on Wednesday that its air force intercepted a Russian reconnaissance aircraft over international waters in the Baltic Sea, describing the flight as a provocation and a potential threat though Polish airspace was not violated.

According to the Polish army, the Russian aircraft was flying in international airspace without a filed flight plan and with its transponders switched off. “The machine was flying in international airspace without a filed flight plan and with transponders turned off. There was no violation of Polish airspace,” the army said.

Polish Defence Minister Wladyslaw Kosiniak-Kamysz said flights conducted without transponders posed risks to other aircraft and warned that Polish pilots would continue to respond immediately to such incidents.