Ukraine claims major drone strike on Russian airfield, killing servicemen and destroying aircraft CNNUkrainian Drone Swarm Attacks Military Airfield Inside Russia BloombergRussia downs dozens of drones as Kremlin warns NATO over Ukraine Al Jazeera EnglishUkraine Claims One of Its Biggest Attacks Inside Russia Just Destroyed Six Bombers The Daily BeastRussia-Ukraine war: Millions of Ukrainians plunged into darkness after power grid strikes The Associated Press