NATO fighter jets shot down multiple Russian drones that violated Polish airspace during an attack on neighboring Ukraine early on Wednesday, as the military alliance denounced Moscow for “absolutely dangerous” behavior that ratcheted up tensions to a new level.

For more than three years, Ukraine has waged an almost nightly battle against Russian attack drones. NATO on Wednesday got a taste of that fight. Polish authorities said they detected 19 violations of their airspace,

Russia is set to increase fortifications by its border with Finland amid heightened tensions between Moscow and the new NATO member. Dmitry Medvedev, the deputy chair of Russia's Security Council, said Moscow was beefing up its infrastructure at the border in response to the Nordic country joining the military alliance in 2023.

Zapad’ military exercises heighten tensions on Nato’s eastern flank, with Nato member Poland warning of ‘critical days’.

By Ben Aris in Berlin The joint Russia and Belarus military exercises get underway on September 12 that will be closely watched by Nato analysts to gauge how strong Russia’s military has become after more than three years of war.

NATO’s Baltic members sent a joint letter to the US Congress, asking for a key military financing initiative to be preserved after the Pentagon said it planned to cut funding for European nations bordering Russia.

Article 4 allows member states to start a formal discussion within the alliance about threats to their security. It does not commit the alliance to military action.