The Polish military scrambled NATO and its own jets after Russian drones entered its airspace while attacking Ukraine, it said early Wednesday, making this the first time Warsaw has directly engaged with Moscow’s assets since the Russian invasion of Ukraine.

“During today’s attack by the Russian Federation targeting objects on the territory of Ukraine, our airspace was repeatedly violated by drone-type objects,” the Polish military operational command said in a post on X.

The military also advised people to stay home as the operation was still ongoing. The areas most at risk were mostly along eastern Poland, namely Podlaskie, which directly borders Ukraine, as well as Mazowieckie and Lublin.

“An operation is underway aimed at identifying and neutralizing these objects … weapons have been used, and service personnel are carrying out actions to locate the downed objects,” the military command said.

“The Operational Command of the Polish Armed Forces is monitoring the situation, and subordinate forces and units remain on full readiness for immediate response,” it added.

This is the first time Poland — or NATO assets — have directly engaged with Russian targets since Russia invaded Ukraine in 2022.

Radars operated by Poland and NATO had tracked several drones before some of them were shot down, the Polish military said in a separate statement on X, adding it was locating the crash sites.

At least three airports across Poland, including the Chopin Airport in Warsaw, were “not available due to unplanned military activity related to ensuring state security,” according to NOTAM alerts on the U.S. Federal Aviation ministration website.

Known as “Notice to Airmen,” these alerts inform aircrews about time-sensitive aerial conditions for safe flying.

“The airport remains open, but no flight operations are currently taking place,” the Chopin airport said in a post on X.

Southwest of Warsaw, the Lublin airport was also closed, according to a NOTAM. The Rzeszów–Jasionka airport, a logistical hub for military and passenger transfers to Ukraine, was also closed.

The Polish engagement came as the Ukrainian air force earlier warned that Russian drones had entered Poland’s airspace and posed a threat to the city of Zamosc, before later removing that statement from the Telegram messaging app, Reuters reported.

The Ukrainian air force issued warnings of dozens of Russian drones and missiles attacking its own territory early Wednesday.

Poland and the U.S. are members of the North Atlantic Treaty Organization, which at its core is a mutual defense pact, meaning an attack on one is an attack on all.

Since Russia invaded Ukraine, neighboring Poland has remained on high alert, especially after a stray Ukrainian missile struck a Polish village just a few months into the war in 2022 and killed two people there. Stray Russian missiles have also briefly entered Polish airspace on at least two occasions.

In the U.S., Secretary of State Marco Rubio told CNN he had been briefed on reports of Russian drones over Poland as he left a dinner with President Donald Trump.

Meanwhile, Sen. Dick Durbin, D-Ill., said the NATO airspace violation was a sign that, “Vladimir Putin is testing our resolve to protect Poland and the Baltic nations.”

“After the carnage Putin continues to visit on Ukraine, these incursions cannot be ignored,” he said on X.