Poland’s military said it scrambled fighter aircraft and shot down Russian drones early Wednesday after they crossed into the country’s airspace from Ukraine.

Prime Minister Donald Tusk said in a statement that a military operation was underway overnight after “multiple violations of Polish airspace” and that “the military used armaments against the objects.”

Poland’s armed forces had earlier said that the country’s airspace was “repeatedly violated by drone-type objects” during a Russian attack on targets in Ukraine, and that Poland’s air defenses had been moved to the “highest state of readiness.”

Polish and NATO military aircraft were deployed and an operation was launched “aimed at identifying and neutralizing the objects.” Military officials advised Poles to stay at home.

Separately, the U.S. Federal Aviation Administration issued a notice saying that Poland’s main international airport in Warsaw was closed due to “unplanned military activity related to ensuring state security.”

Tusk said in his statement on X that he was in constant contact with Poland’s defense ministry and President Karol Nawrocki.

It was not clear how many drones had entered Polish airspace or been shot down.

This is a developing story.