Tusk told parliament that Poland had identified 19 violations of its airspace overnight and shot down at least three drones, adding that no one was harmed in the "Russian action".

"The allied consultations I am referring to have now taken the form of a formal request to invoke Article 4 of the North Atlantic Treaty," he added.

The North Atlantic Council, NATO's main political decision-making body, met on Wednesday morning for its regular weekly meeting.

However, according to diplomats, the allies decided that the meeting would be held under Article 4 of the alliance treaty.

Under Article 4, any member can call urgent talks when it feels its "territorial integrity, political independence or security" are at risk.

The Polish case marked the eighth time the article has been invoked since the alliance was founded in 1949.

Wednesday's talks are the third time Article 4 has been invoked to address Russia's incursions into and invasion of Ukraine.

NATO's collective security is based on its Article 5 principle: if one member is attacked, the entire alliance comes to its defence.

That article has only been invoked once in the history of NATO, following the September 11, 2001 attacks in the United States.

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