Officials said the military operation was ongoing and urged people to stay at home, naming the regions of Podlaskie, Mazowieckie and Lublin as most at risk.

Two airports in the capital Warsaw - the major hub Chopin Airport and Warsaw Modlin Airport - were closed. Also suspended were Rzeszów-Jasionka Airport - which is the air hub closest Ukraine - and Lublin Airport according to a notice posted to the US Federal Aviation Administration's website.

Polish authorities have closed Warsaw International Airport and Polish and NATO aircraft have been scrambled as reports have surfaced of Russian drones over the country.