Poland scrambled fighter jets and closed its airspace over the southeastern cities of Lublin and Rzeszów today, citing unplanned military activity related to ensuring country’s security. The move followed Russia’s massive overnight assault on Ukraine. President Volodymyr Zelenskyy said Moscow launched around 500 drones and 40 missiles, killing at least four people Kiev. 

Poland’s military said it responded to the strikes by launching Polish and allied aircraft to secure airspace and protect citizens. Officials said, North Atlantic Treaty Organization (NATO) aircraft also joined amid concerns of a possible incursion.

The incident comes amid rising tensions along NATO’s eastern flank. Poland, Romania, and Estonia have all recently reported Russian airspace violations. Early this month, Poland downed Russian drones that crossed its border – the first such incursion into NATO territory since the war began.