In a significant escalation of hostilities, Ukraine launched its largest drone attack on Moscow in over a year, resulting in at least four fatalities and multiple injuries. Local officials reported that three people died in the Moscow region and one in the Belgorod region, which borders Ukraine. President Volodymyr Zelensky confirmed the operation, highlighting Ukraine's ability to strike targets over 500 km (310 miles) from its border despite robust Russian air defenses. This attack follows a series of heavy drone and missile strikes by Russia on Kyiv, prompting Zelensky to vow retaliation. Moscow Mayor Sergei Sobyanin stated that air defenses had intercepted 81 drones aimed at the capital since midnight, marking the attack as the largest on Moscow in over a year. Damage included several residential buildings and infrastructure, although the oil refinery's operations were not affected. Zelensky characterized the attack as a justified response to Russia's ongoing aggression, while Russian officials condemned it as a terrorist act targeting civilians.