Polish President Karol Nawrocki signed a classified resolution this week allowing NATO forces to operate on Polish soil, according to Poland’s National Security Bureau.

The move comes as part of the alliance’s new “Eastern Sentinel” initiative that began on 12 September to strengthen Europe’s eastern flank.

NATO troops will now reinforce Polish defenses under the program, though the presidential resolution remains classified, the Poland’s National Security Bureau reports.

Secretary General Mark Rutte said military operations would begin “in the coming days” with forces from Denmark, France, Britain, Germany and other allies. Ground troops will deploy across eight countries, with room to expand if needed.

The catalyst?

Russia’s massive assault on Ukraine on 10 September that violated Polish airspace. Moscow launched over 400 drones and more than 40 cruise and ballistic missiles that night, killing one person and injuring several others in Ukraine.

However, 19 Russian drones also crossed into Polish territory—not the usual strays from Ukraine, but aircraft flying directly from Belarus. 

Poland scrambled advanced fighters, including F-35s and F-16s, marking the first time Polish forces used airborne weapons against the unmanned vehicles. Even with sophisticated aircraft deployed, Polish forces couldn’t intercept all targets.

The incursions triggered NATO’s Article 4, requiring member states to consult when any ally faces threats to territorial integrity or security. However, NATO decided not to treat this deliberate drone incursion as an attack.

The Eastern Sentinel rollout suggests the alliance views recent escalations as more than isolated incidents requiring a measured but substantial response along NATO’s eastern frontier.

Trump’s limited response to Russian drones entering Polish airspace this week has worried European allies who doubt whether he’s serious about NATO defense duties, Reuters reported.