An unidentified aerial object entered the airspace of Nato-member Poland from the direction of the border with Ukraine on Friday morning, the Polish army's Operational Command said.
"In the morning, an unidentified aerial object entered the airspace ... and from the moment it crossed the border until the signal disappeared, it was observed by the radars of the country's air defence system," it said on social media platform X.
"In accordance with applicable procedures, the operational commander of the armed forces mobilised the available forces and resources at his disposal."
Private broadcaster TV Republika had reported that a search for the object was happening near the town of Hrubieszow in southern Poland. Reuters was unable to immediately confirm this information.
"We received information that an object appeared on the radar near Hrubieszow," Krzysztof Komorski, governor of the Lublin region said on X. "We have no confirmation that it fell within our region."
Russia targeted Ukraine with 158 drones and missiles overnight in one of its biggest air attacks since the beginning of the full-scale invasion, targeting critical infrastructure, industry and military facilities, the Ukrainian military said.
A stray Ukrainian missile struck the Polish village of Przewodow in southern Poland in November 2022 in an incident that raised fears of the war in Ukraine spilling over the border.
In April, a military object was found in a forest close to the village of Zamosc near the northern city of Bydgoszcz. It was later reported to be a Russian missile.
