The emergency warning was supposed to be issued in the districts of the city where an approaching plane was spotted, spokeswoman for Warsaw's city hall Magdalena Lan explained. "Various urban services are supposed to react accordingly when an aircraft appears," she said.
Warsaw's international Chopin Airport also took part in the drills, dubbed the Renegade Kaper.
"We are holding an exercise related to a possible terrorist airstrike," airport spokesman Przemysław Przybylski said, adding that the main task was to check all the related procedures.
The air raid defense drills were held in other polish cities, including Krakow.
The drills were part of Operation Atlantic Resolve launched by the US in 2014 to expand the presence of US forces and enhance exercises close to the Russian border under the pretext of protecting Washington's European partners, especially in Eastern Europe, from Moscow's putative threat and alleged meddling in Ukrainian affairs.