KYIV, Ukraine — The Ukrainian military said Wednesday that it struck a fuel storage depot deep inside Russia, causing a huge blaze at the facility that supplies an important Russian air base. Russian officials acknowledged a major drone attack in the area, and said that authorities had set up an emergency command center to fight the fire.

Ukrainian drones attacked the Russian cities of Saratov and Engels, where Russia has an air base for its fleet of strategic bomber planes, the regional governor said on Wednesday. Governor Roman Busargin said the two cities had been subject to a mass drone attack and there was damage to an industrial site.

Russia launched doxens of drones against cities and towns in southern and eastern Ukraine overnight killing three people and injuring at least 23, Ukrainian authorities said.