Ukrainians conducted another successful attack on Russian fuel infrastructure. On Tuesday morning, drones attacked a refinery in Saratov. A series of explosions were also heard near an airbase close to the city of Engels.

"The Saratov Oil Refinery is one of the key facilities in Russia's fuel infrastructure. Its refining capacity reaches 7 million tons of oil annually," Andrii Kovalenko, head of Ukraine's Center for Countering Disinformation,

Overnight Russian drone attacks sparked a fire in Kyiv and injured a woman and damaged several houses in the northeastern city of Sumy, Ukrainian officials said on Monday. The Ukrainian military said on Monday that it had shot down 61 out of 83 drones with 22 more likely downed by electronic warfare.

Officials say Russian forces have targeted Ukraine’s energy and gas infrastructure in a “massive” nighttime missile attack, while Ukrainian drones struck an important oil refinery inside Russia.

The attack on the major oil refinery is an attempt by Ukraine to disrupt the Russian military's ability to resupply frontline troops.

Ukraine has, for some time, fielded large "mothership" drones that can carry and eventually deploy a set of smaller attack drones. This approach can, for example, get light and fast FPV attack drones behind the front lines before releasing them, thereby extending the attack drones' limited range.

A Ukrainian drone attack overnight sparked a fire at an oil depot in Russia's southern region of Krasnodar that has since been extinguished, regional officials said on Wednesday.

Ukraine has launched its second major drone attack in a week against Russian oil refineries hundreds of miles from its borders.

Recent social media videos show Ukrainian forces using drones similar to IEDs. The drones sit next to roads and then strike Russian military vehicles when they pass.