NATO aircraft have been conducting regular surveillance around Ukraine since the Russian invasion began. The aircraft flying above Poland on Tuesday was monitoring events in Ukraine.
The NATO official did not say who launched the missile that was tracked landing in Poland, nor where it was fired from.
Russia launched a large-scale missile strike on Ukraine on the afternoon of 15 November. Several Russian missiles crossed into Poland, landing not far from the Polish-Ukrainian border. Prime Minister Mateusz Morawiecki of Poland has urgently convened a meeting of the Committee of the Council of Ministers for National Security and Defence.