Drones operated by Ukraine’s Security Service (SBU) struck five Russian fighter jets overnight on Aug. 4 at an airfield in Saky, a city in Russian-occupied Crimea, the agency said.

Ukrainian drones, in a Special Operations Center “A” mission, destroyed a Su-30SM aircraft, damaged another, hit three Su-24s, and struck an aviation weapons depot.

The Saky airbase plays a critical role in Russia’s military operations in the Black Sea, and the damage from the Ukrainian strike is considered “significant,” with a single Su-30SM jet valued between $35 million and $50 million, according to the SBU.