NATO on Friday launched a new mission, dubbed Eastern Sentry, to bolster the defence of the alliance’s eastern flank after an incursion of Russian drones into Polish airspace earlier this week, officials said.
NATO Secretary‑General Mark Rutte said the operation would begin Friday evening and would integrate a range of air and ground bases and other assets provided by member states. "It's reckless and unacceptable. We can't have Russian drones entering allied airspace," Rutte said, announcing the mission. Allies including Denmark, France, the United Kingdom and Germany committed forces, and other members were expected to join, NATO officials said. NATO’s top commander, Alexus Grynkewich, said the alliance would "defend every inch" of its territory and that the steps taken should reassure Poland and citizens across the alliance.
The announcement came as Russia and Belarus launched a major joint military exercise, Zapad‑2025, on Friday. The manoeuvres, scheduled to run through Tuesday, Sept. 16, will be held on Russian and Belarusian territory and in adjacent maritime areas, including the Baltic and Barents seas, according to Moscow’s Defence Ministry. The ministry said troops would practice planning the use of nuclear weapons and operate the new nuclear‑capable Oreshnik ballistic missile that Russia has said it will station in Belarus.
The drills follow a Wednesday incident in which about 20 Russian attack drones crossed into Polish airspace, prompting NATO allies to scramble jets and sharply raising tensions on the alliance’s eastern border. Poland and several European capitals described the incursion as a deliberate provocation; Moscow said it was not targeting Poland and suggested some drones had veered off course. Belarus said the drones had come from the direction of Ukraine.
Poland responded by sealing its border with Belarus and moving tens of thousands of troops to the frontier. Prime Minister Donald Tusk said he had dispatched 40,000 personnel and ordered barbed wire and barricades erected at crossings, warning of "critical days" and saying Poland was closer to "open conflict" than at any point since World War II. Interior Minister Marcin Kierwinski said the border closure was a precautionary measure for the duration of the drills "for the safety of our citizens."
France announced it would send three Rafale fighter jets to help protect Polish airspace, President Emmanuel Macron said. Lithuania and Latvia declared partial airspace closures and announced stepped‑up border protections. Western leaders said European states rapidly coordinated their responses to the drone flights even without immediate U.S. military action, underscoring NATO’s ability to mobilise allied assets in the region.
The Russian defence ministry described Zapad‑2025 as aimed at improving commanders’ planning skills, cooperation and field training of regional and coalition groupings of troops. It said the exercise would include a first stage simulating repelling an attack against Russia and Belarus and a second stage focused on restoring the territorial integrity of the so‑called Union State.
The Kremlin has repeatedly maintained the drills are routine and not directed at any country. Kremlin spokesman Dmitry Peskov said the exercises were "planned exercises" and "not aimed against anyone." Still, the planned training with nuclear‑capable systems and explicit mention of nuclear strike simulations has heightened concerns among NATO members.
Analysts warned the combination of the drone incursion and the drills could amount to a test of NATO readiness and resolve. Vassily Kashin, a military analyst and member of the Russian International Affairs Council quoted by news agencies, said the exercises were both a demonstration and real combat training and insisted Russia must be ready to defend Belarus if necessary. Other analysts cautioned that past Zapad manoeuvres had been used to build up forces subsequently employed in offensive operations. Zapad‑2021, which was expected to involve roughly 12,800 servicemen, saw much larger reported numbers and preceded Moscow’s wider offensive in Ukraine.
Poland has argued the drills are designed in part to simulate operations in the Suwałki corridor, a narrow stretch of territory between Poland and Lithuania that NATO officials and Warsaw consider a strategic vulnerability. Polish officials said that Moscow has previously used large‑scale exercises to rehearse operations against NATO territory.
U.S. President Donald Trump, speaking on a U.S. talk show, said his patience with President Vladimir Putin was "running out fast" and hinted at tougher sanctions, while also urging negotiations and suggesting Kyiv and Moscow both have roles to play in resolving the conflict in Ukraine. Outgoing French foreign minister Jean‑Noël Barrot said he would summon the Russian ambassador and called the drone flights an unacceptable strategy to intimidate and test NATO allies. Ukrainian President Volodymyr Zelensky described the airspace violation as a "dangerous precedent for Europe."
Minsk had earlier indicated a smaller force would take part in the 2025 drills than in 2021. Belarus said in January that 13,000 troops would be involved but reduced that number by about half in later statements and said it intended to invite observers, including from NATO countries. Russia’s decision to station tactical nuclear weapons in Belarus and to include the Oreshnik missile in exercises has nonetheless given the drills a new and more worrying dimension for neighbouring states.
NATO officials said the Eastern Sentry mission would be closely coordinated and would demonstrate the alliance’s commitment to collective defence. Germany’s chief of defence, Carsten Breuer, said NATO would "be on our guard" for the duration of the exercises, and allies indicated they would continue close monitoring of Russian and Belarusian movements. Poland’s government warned that the drills and the drone incident would shape security planning in the region for the coming weeks.
The Zapad‑2025 drills and NATO’s response mark a new phase of tension on Europe’s eastern flank, where military activity linked to the war in Ukraine has increased the risk of miscalculation. Both sides have presented their actions as defensive; allied officials said they would continue to watch developments closely and to take measures to reassure and protect NATO members along the alliance’s eastern border.