Poland has scrambled fighter jets and helicopters after a "massive" Russian attack on Ukraine, including a large number of drones.
The Operational Command of the Polish Armed Forces said it had also put ground-based air defense and radar reconnaissance systems on high alert.
The authorities stressed that the action was "preventive in nature" and aimed at securing Polish airspace, especially near areas subject to Russian strikes.
The Operational Command added that it was monitoring the situation and that the army remained ready for an immediate response.