Patriot batteries are considered Ukraine's top defense against Russia's ballistic missiles. Russia often mixes up how it attacks Ukraine with ballistic and cruise missiles -- from firing decoys to tweaking trajectories midflight -- and Kyiv says it's funneling that battlefield intel to US Patriot interceptor makers to inform upgrades for better performance.

Ukrainian President Volodymyr Zelenskiy has repeatedly urged allies to provide more air defenses as stockpiles run low, and NATO Secretary General Mark Rutte said Ukraine "urgently needs more air defense" to defend itself against ongoing Russian attacks.