Poland shot down drones in its airspace on Wednesday with the backing of military aircraft from its NATO allies, the first time a member of the Western military alliance is known to have fired shots during Russia's war in Ukraine.

Polish Prime Minister Donald Tusk told parliament it was "the closest we have been to open conflict since World War II", although he also said he had "no reason to believe we're on the brink of war".

Moscow denied responsibility for the incident, with a senior diplomat in Poland saying the drones had come from the direction of Ukraine.