Ukraine continues to cripple Russia's energy sector by hitting numerous oil refineries, depots, chemical plants, and more with drones.

A drone attack overnight on Jan. 14 caused damage to an industrial facility in the city of Engels, located in Russia's Saratov region. Engels lies around 600 kilometers (370 miles) from the front lines in Ukraine.

Ukraine launched waves of long-range strikes, including its ATACMS and Storm Shadow missiles, at targets inside Russia.

Europe warns its airlines to stay away through next summer, as Ukraine turns skies of western Russia into a battlefield.

The fire at the oil depot in the Liskinsky district of Voronezh Oblast, Russia, which was attacked by drones earlier, was extinguished all night and as of the morning, the firefighting is ongoing, the governor of the oblast,

Kyiv targeted Russian factories developing weapons, an oil depot, a refinery and air defense systems, a Ukrainian official said.

While the ground war in eastern Ukraine has settled into a grinding war of attrition, where Russian forces sacrifice hundreds, sometimes thousands, of troops a day, for small, incremental advances, the air war has the two sides inflicting significant losses on each other's energy sector.

Located in Saratov Oblast, over 750 kilometers from the Ukrainian border, Engels airbase is home to Russian heavy bombers.

Ukraine's latest aerial bombardment was spread across 12 Russian regions, with targets including an oil depot and an airfield in Engels.

Russia’s military on Tuesday said it would retaliate against Ukraine after Kyiv attacked Russian regions by firing six US-made ATACMS ballistic missiles, six UK-made Storm Shadow cruise missiles and launching one of the biggest drone attacks to date.

One of the farthest Ukrainian attacks inside Vladimir Putin’s country was reported to have taken place 1,800km (1,100 miles) over the border. The operator is part of the 14th Separate UAV Regiment, one of the most technologically advanced units within the Armed Forces of Ukraine.