Poland's military announced during the night to Wednesday that they had sent up fighter jets, and just before 04 Swedish time, the military confirmed that the country's airspace had been violated "several times".
Prime Minister Donald Tusk writes on X that an operation is underway.
"The military has used weapons against the targets. I am in constant contact with the president and the minister of defense."
Earlier during the night, Ukraine's air force had in a post on Telegram warned that drones had flown in over Poland during an attack on the western parts of Ukraine. The post was later removed.
Several airports in Poland have been closed as a result of the incident and the military is urging residents to stay indoors.
Poland is a member of NATO and allied aircraft are to be part of the operation.
