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.

Ukraine launched what local officials called a "massive" drone attack far behind the frontlines in the Russian city of Engels.

The Russian city of Saratov and nearby Engels, which hosts a major airbase, "were subjected to a massive UAV attack last night," the regional governor said.

It reported multiple explosions and a big fire at "Kristal" oil depot, which it said provided fuel to the "Engels-2" military airfield, where Russia's strategic bomber fleet is based. "The strike of the oil depot creates serious logistical problems for the strategic aviation of the Russian occupiers and significantly reduces their ability to strike at peaceful Ukrainian cities and civilian objects,

Ukraine launched an overnight strike deep inside Russia that set fire to an oil depot in the city of Engels that serves an air base for Russian nuclear bomber planes, the Ukrainian military said on Wednesday.