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 conflict 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. European leaders said it justified a collective response. There was no immediate response from Washington.

Poland said 19 objects had entered its airspace during a large Russian air attack on Ukraine, and that it had shot down those that posed a threat. 

Tusk called the incident a "large-scale provocation" and said he had activated Article Four of NATO's treaty, under which alliance members can demand consultations with their allies.

A NATO spokesperson said NATO chief Mark Rutte was in touch with the Polish leadership and the alliance was consulting closely with Poland.

A source said NATO was not treating the incident as an attack but as an intentional incursion. Polish F-16 fighter jets, Dutch F-35s, Italian AWACS surveillance planes and mid-air refueling aircraft jointly operated by NATO were involved in the overnight operation, according to the source.

Russia's top diplomat in Poland, cited by RIA state news agency, called the accusations of an incursion "groundless" and said Poland had not given any evidence that the drones shot down were of Russian origin.

Tusk said some of the drones had entered Polish airspace directly from Belarus, rather than from Ukrainian airspace.

During the incident, the Operational Command of the Polish Armed Forces urged residents to stay at home, with three eastern regions at particular risk. "This is an act of aggression that posed a real threat to the safety of our citizens," it said.

Several Polish airports were temporarily closed, including one that has been used as the main access point for Western officials and supplies travelling to Ukraine over land.

Countries bordering on Ukraine have reported occasional Russian missiles or drones entering their airspace in the past during the conflict, but not on such a large scale, and they are not known to have shot them down. Two people were killed in Poland in 2022 by a Ukrainian air defence missile that went astray.

Footage showed a blackened spot in a brown field in southeastern Poland where drones fell.

Russian response 

Russia has long said it has no intention of stoking a war with NATO, and that Western European countries suggesting it is a threat are trying to worsen relations.

Cited by the TASS news agency, Russia's defense ministry said no targets in Poland were planned for attack, that the range of the drones that crossed the border does not exceed 700 kilometers, and that it was ready to hold talks with Poland's defense ministry.

Asked about the drones and Tusk's remarks, Kremlin spokesman Dmitry Peskov said: "In this case, we would not like to comment on it in any way. This is not our responsibility - it is the prerogative of the defense ministry."

Peskov said that the Kremlin had not received any requests for contact from Poland, but dismissed European Union and NATO accusations that Russia had carried out a provocation.

"The leadership of the EU and NATO accuse Russia of provocations on a daily basis. Most of the time, without even trying to present at least some kind of arguement," Peskov said.

A Russian diplomat in Warsaw said that the drones had come from the direction of Ukraine, Russian state news agency RIA reported.

"We know one thing – these drones were flying from the direction of Ukraine," Russia's charge d'affaires in Warsaw, Andrei Ordash, was quoted as saying after leaving the Polish Foreign Ministry.

Belarus says it shot down stray drones 

Belarus said it had shot down some drones which went astray due to electronic jamming during an exchange of strikes between Russia and Ukraine, and that Minsk had informed Poland and Lithuania of the approach of the drones.

The statement by Belarus Chief of the General Staff Major General Pavel Muraveiko did not say whose drones – also known as unmanned aerial vehicles (UAVs) – went astray.

"During the night-time exchange of strikes by UAVs between the Russian Federation and Ukraine, the Air Defense Forces and assets of the Republic of Belarus on duty continuously tracked UAVs that had lost their track as a result of the impact of the parties' electronic warfare assets," Muraveiko said in a statement issued in English.

Muraveiko said Poland and Lithuania were informed of the approach of the drones.

"This allowed the Polish side to respond promptly to the actions of the drones by scrambling their forces on duty," Muraveiko said. "The Republic of Belarus will continue to fulfil its obligations within the framework of the exchange of information on the air situation with the Republic of Poland and the Baltic countries."