Defence Minister Guido Crosetto on Wednesday confirmed reports that an Italian surveillance plane was involved in NATO's response after Russian drones violated Poland's airspace overnight.

"Italian aircraft are part of NATO and are ready to defend our allies, as we expect their allies would do if Italy were threatened," Crosetto said on the sidelines of the E5 ministerial meeting in London.

"NATO is united.

"The most serious violation of European airspace since the beginning of the war took place in Poland last night," he continued.

"A deliberate attack with more than 20 Russian drones.