NATO will send more warplanes and air defense systems to the eastern flank in response to Russian drone incursions into Polish airspace, the alliance’s top officials announced Friday.

“Today, NATO is launching Eastern Sentry to bolster our posture along eastern flank,” Secretary-General Mark Rutte told reporters.

On Wednesday, Polish and Dutch fighter jets scrambled to shoot down Russian drones in Poland’s airspace, in one of most serious violations of a NATO country’s sovereignty.

Eastern Sentry, which starts Friday, will be modeled after Baltic Sentry, where frigates, aircraft and drones monitor the Baltic Sea. NATO allies will also experiment with new technologies such as counter-drones, sensors and weapons in Eastern Sentry, said Supreme Allied Commander Europe Gen. Alexus Grynkewich.

The mission — described as an “entire new defense design” — will also integrate current “individual air policing actions and individual ground based air defenses.” Denmark, France, the U.K. and Germany have already offered contributions including fighter jets, ships and ground-based air defense systems.

Grynkewich hailed Wednesday’s operation in Polish airspace as a success, but said NATO is working to get “lower cost weapons that we can use to defend ourselves to make this a sustainable operation over time.”

Rutte — echoing U.S. President Donald Trump but going against Poland and Germany’s assessment — refused to explicitly say that the Russian incursion was intentional.

“We are still assessing,” he said. “Whether or not Russia’s actions were deliberate, they violated NATO air space. The question is relevant but not that relevant — in both cases, it’s reckless, unacceptable.”