Nato members began moving forces and air-defence equipment to the alliance's eastern flank after Poland reported what officials described as an unprecedented incursion of Russian drones into its airspace.
Polish authorities said three drones were shot down in the early hours of Wednesday after crossing into Polish airspace and that additional drones crashed and were later found across eastern Poland. Warsaw requested an urgent United Nations Security Council session to be held on Friday at 19:00 GMT to address the incident.
Polish Prime Minister Donald Tusk called the episode a "large-scale provocation" by Russia. The Kremlin said it had no further comment on claims that Moscow deliberately sought to stoke tensions in Poland. NATO's top military commander, Gen. Alexus Grynkewich, said it was not yet known whether the incursion was intentional and that the precise number of drones that crossed into Polish airspace remained to be determined.
In Warsaw on Thursday, Defence Minister Wladyslaw Kosiniak-Kamysz listed offers of support from alliance partners. He said the Netherlands would deploy air-defence systems, artillery and 300 troops, and that the Czech Republic would send helicopters and about 100 soldiers. He added that France and the United Kingdom could deploy aircraft to help secure Nato's eastern flank, and that Lithuania would receive a German brigade and improved warning of aerial launches from Russia that might cross its airspace.
President Karol Nawrocki said the incursion was "nothing more than an attempt to test our capabilities," echoing concerns voiced by leaders in Germany and France. Ukraine's President Volodymyr Zelensky offered to provide guidance and training to Western military personnel on defending against Russian aerial attacks and called for a joint air-defence system to shield Europe from similar threats.
Poland announced steps to tighten security along its eastern borders. Authorities said they would set restrictions for drones and small aircraft along the frontiers with Belarus and Ukraine. The government also said it would close its border with Belarus "for national security reasons... in connection with the Zapad manoeuvres," a reference to planned joint military exercises between Belarus and Russia due to begin on Friday. Latvia said it would close its eastern airspace for a week.
Lithuanian military intelligence chief Mindaugas Mazonas said the Zapad 2025 drills would be smaller than previous iterations, involving up to about 30,000 troops, compared with roughly 200,000 during the last large-scale exercises held several months before Russia's full-scale invasion of Ukraine in 2022.
Allies have emphasized caution while investigators seek to establish the facts. Gen. Grynkewich said Nato would increase defensive measures and intelligence sharing for countries bordering Russia and Belarus. He also said steps would be taken to provide Lithuania with greater warning of aerial launches that could cross into its airspace.
Reaction among Western leaders varied. The United States president, Donald Trump, posted briefly on social media asking, "What's with Russia violating Poland's airspace with drones? Here we go!" without elaborating. Polish officials said Washington had participated in consultations that they said reaffirmed allied unity.
Experts remain divided over whether Moscow intended to send drones into NATO territory or whether the crossings were accidental. While incidents of Russian missiles or drones straying into NATO countries have occurred since Russia's invasion of Ukraine in February 2022, Polish and some European leaders called this week's events the most serious of their kind in the period since then.
Nato's stepped-up deployments aim both to deter further incidents and to reassure eastern member states. Warsaw said it had received "concrete declarations" of support from partners after years in which leaders said Poland had sometimes been offered only rhetorical solidarity. The alliance's moves underscore heightened tensions along the eastern flank as the Zapad exercises begin and as allies press to clarify whether the drone incidents represent a deliberate escalation or an operational spillover from the conflict in Ukraine.
A United Nations Security Council meeting is scheduled for Friday at 19:00 GMT, where Poland and other members will discuss the incursions. Investigations by Polish and allied authorities into the origin, trajectory and intent behind the drones are ongoing.