A Russian military Mi-8 helicopter briefly entered Polish airspace from the Russian exclave of Kaliningrad on Wednesday, Polish military officials said.

The helicopter remained in Polish airspace for 42 seconds and penetrated to a maximum depth of about 300 meters (328 yards), according to the Polish Army Operational Command, The Caspian Post reports.

“Fighter aircraft were scrambled, and ground-based forces and assets remained on standby,” the command said in a post on X. It added that the nature of the incident indicated that Russia was once again testing the readiness of Poland’s air defense.

Poland, a NATO member, remains on heightened alert over possible airspace incursions linked to Russia’s war in neighboring Ukraine.