Article 4 can be invoked by any NATO member that feels threatened.

Poland said it scrambled its own and NATO air defenses to shoot down drones on Sept. 10 after a Russian air attack on western Ukraine, the first time in the Ukraine war that Warsaw has engaged assets...

Earlier, the Ukrainian Air Force said on the Telegram messaging app that drones were heading west and threatening the city of Zamosc in Poland, but the statement has since been deleted, Reuters repor...