Operation Eastern Sentry

Operation Eastern Sentry (or Eastern Sentinel) is a NATO operation to protect territory along NATO's eastern flank, made in response to an Article 4 declaration by the Polish government in response to a Russian drone incursion into Poland on 9–10 September 2025. Operation Eastern Sentry was launched two days later on 12 September 2025, without a stated end date. The primary purpose of the operation is to increase NATO's capacity—in the air, at sea, and on the ground—to counter military threats posed by Russia, in particular to intercept Russian drones violating the airspace of NATO member states. Whereas this responsibility was previously carried out by the individual member states, Eastern Sentry established a collective policy and conduct for aerial defence on NATO's eastern flank.