NATO is preparing both military and political responses after Russian drones allegedly violated Polish airspace during overnight strikes on Ukraine, marking the first time allied aircraft have shot down drones in NATO territory since the war began.

According to a source familiar with the matter, the response will be aimed at strengthening deterrence across NATO’s eastern flank. The alliance emphasized that its actions will remain defensive in nature.

NATO response underway

The incident, which took place on the night of September 9–10, involved 19 drones, several of which were destroyed by NATO forces after crossing into Polish airspace.

NATO Secretary-General Mark Rutte condemned Russia’s actions as “reckless and dangerous,” warning that the alliance takes any violation of its borders seriously.

“Whether intentional or not, it is absolutely reckless. A full assessment of the incident is ongoing,” Rutte told reporters Wednesday.

The military response is being coordinated by Supreme Allied Commander Europe Alexus Grynkewich, who is overseeing planning and supply assessments. The alliance said any measures would focus on reinforcing air defenses and deterrence posture along its borders.

Politically, an initial response came on Wednesday as NATO leaders issued a joint condemnation of Russia’s actions.

Warsaw deploys 40,000 troops to eastern border

Poland has formally asked its allies for additional air defense systems and counter-drone technologies following the attack. Warsaw has also announced the deployment of 40,000 soldiers to its eastern border, up from about 10,000, in anticipation of the Zapad-2025 military exercises in Belarus beginning September 12.

Deputy Defense Minister Cezary Tomczyk told Polsat News that the buildup was essential to counter potential threats from the Russian-Belarusian drills, which are viewed as offensive in nature.

“Poland has been preparing for the Zapad-2025 exercises for many months… In the coming days, we will have approximately 40,000 soldiers on the border,” Tomczyk said.

He also linked the drone incursion to the exercises, describing it as part of a broader pattern of hybrid pressure tactics.

Russian, Belarusian denials

Moscow has denied involvement in the incident, with the Kremlin and both the Russian Ministry of Foreign Affairs and Defense Ministry asserting that the drones did not belong to Russia. Belarus suggested that some drones may have “got lost” and said it had notified Poland and Lithuania of the situation.

The European Union condemned the airspace violation, with EU Foreign Policy Chief Kaja Kallas calling it "a serious escalation of Russia’s actions, an aggressive and reckless act that threatens the security of EU citizens, regional stability, and international peace.”

Ukraine pledged to help Poland enhance its early warning and detection systems to better counter future drone threats.

This comes as Russia and Belarus conduct large-scale military drills just across the border. While NATO has stressed its defensive posture, the combination of the Zapad-2025 exercises, drone incursions, and troop deployments is seen as one of the most serious escalations on the alliance’s eastern front in recent years.