NATO fighter jets were scrambled and air defense units put on high alert early Sunday morning following a large-scale Russian drone and missile assault on Ukraine, according to Poland’s Operational Command.

In an official statement shared on X (formerly Twitter), the command confirmed that “due to the activity of the Russian Federation’s long-range aviation, which is carrying out strikes on the territory of Ukraine, Polish and allied aviation has begun operating in our airspace.”

The statement added that “on-duty fighter pairs have been scrambled, and ground-based air defense systems as well as radar reconnaissance have reached a state of highest readiness.” The moves were described as “preventive” and focused on securing Polish airspace and protecting civilians, particularly in eastern regions close to the Ukrainian border.

Among the NATO assets mobilized were Dutch F-35 stealth fighters and a German Patriot surface-to-air missile system. Polish authorities briefly closed airspace over the Lublin and Rzeszow regions during the alert, which lasted approximately three and a half hours. No violations of Polish airspace were reported during the incident.

The immediate trigger for NATO’s posture was a coordinated Russian strike on multiple Ukrainian cities, including Kyiv, Zaporizhzhia, Khmelnytskyi, Sumy, and Odesa. According to President Volodymyr Zelenskyy, the attacks persisted for more than 12 hours.

Ukraine’s Air Force reported that Russia launched a total of 593 drones and 50 missiles in what has become the largest combined aerial assault on Ukraine since September 7. Air defense systems managed to intercept or neutralize 566 drones and 45 missiles, but at least five missiles and 31 drones penetrated defenses, striking 16 locations.

In the capital, at least four people were killed, including a 12-year-old girl, said Kyiv City Military Administration head Timur Tkachenko. Local officials confirmed that 14 others were injured as Russian drones targeted multi-story residential buildings across five city districts.

Mayor Vitali Klitschko reported that a five-story apartment building in the Solomyanskyi district had been partially destroyed and caught fire. Other impacts were reported on a state-run medical facility, private homes, vehicles, warehouses, and a children’s educational center.

Sunday’s developments come amid persistent concerns about the security of NATO’s eastern border. Although there were no new airspace breaches, the memory of the September 10 incident, when multiple Russian drones crossed into Polish airspace and were intercepted by NATO jets, remains fresh.

As the conflict intensifies, NATO’s rapid military response underscores the alliance’s growing unease over spillover effects from Russia’s ongoing aggression in Ukraine. Secretary-General Mark Rutte and other Western leaders have warned that further escalation could necessitate even more robust defensive actions across allied territories.