KYIV, Dec 22 - Ukrainian drones struck a major Russian fuel depot for the second time in just over a week on Sunday, according to a senior Russian regional official, as part of a “massive” cross-border attack on fuel and energy facilities that Kyiv says supply Moscow’s military.

The strikes came days after Russia launched sweeping attacks on Ukraine’s already battered energy grid, threatening to plunge thousands of homes into darkness as winter tightens its grip over the region, and as Russia’s all-out invasion of its neighbor nears the three-year mark, The Associated Press reported.

A fire broke out at the Stalnoy Kon oil terminal in Russia’s southern Oryol region, local Gov. Andrey Klychkov said in a post on the Telegram messaging app, adding Russian forces downed 20 drones targeting “fuel and energy infrastructure” in the province.

Russian independent news outlet Astra shared video of what it said was an explosion at the site, showing a massive orange blaze lighting up the night sky. While the clip could not be independently verified, it was later shared by a Ukrainian security official who described it as footage from Oryol.

The official, Andriy Kovalenko of the Council of National Security and Defense, claimed the Oryol fuel depot supplies Russian forces fighting in Ukraine and southern Russia, including the Kursk province where Ukrainian troops have dug in following a lightning incursion in August.

According to Klychkov, the Russian local governor, the fire was extinguished hours later and did not cause casualties or “significant” damage.

Ukraine’s military previously claimed to have struck the Stalnoy Kon terminal with drones on Dec. 14, causing a “powerful” blaze.

Meanwhile, Russian President Vladimir Putin on Sunday vowed retaliation after Ukrainian drones the day before struck residential buildings in the city of Kazan, in the Tatarstan region over 600 miles (1,000 kilometers) from the front line.

Speaking to Tatarstan’s regional governor, Rustam Minnikhanov, Putin asserted that anyone attacking Russia has to reckon with Moscow inflicting “many times greater damage” in return, but did not elaborate. His remarks were carried by Russian state news agencies. (ap/ez)