Flames have engulfed a major oil refinery following a reported explosion in the Russian city of Volgograd.
Footage circulated online shows a large fire at the site following a series of Ukrainian attacks at similar sites across the country.
Local authorities have attempted to play down the incident, claiming that it was caused by “internal factors.”
However, local sources have reported hearing a “loud explosion” prior to the incident.
Local news outlet V1 reports: “Unit 18 and two heat exchangers caught fire at the plant. The fire has been extinguished, no one was killed or injured in the incident, the exact cause of the fire is being established, but it is already known that the fire was caused by an emergency situation that had nothing to do with any external influence.”
The incident occurred 24 hours after Ukraine launched a wave of devastating drone and missile attacks overnight, targeting industrial facilities and oil depots in several Russian cities.
Ukrainian drones targeted several plants crucial to the Russian war effort, including one of the country’s largest manufacturers of high-strength plastics situated on the outskirts of the city of Kazan.
Footage posted online by locals showed a raging inferno after the plant was struck, with reports that a gas tank was hit, causing a large explosion.
In a press release, local officials said: “Today at 5:20 am in the suburbs of Kazan, a gas tank caught fire as a result of a UAV attack.”
They added that there were no reports of any casualties and that the head of Tartarstan. Rustam Minnikhanov, who has been serving as head of the region since 2010, later inspected the damage.
Another oil depot was also hit by Ukrainian drones on Monday evening as the cheap, unmanned weapons were flown into a site in Engels for the second time this year.
The site had been hit on January 8, with the resulting flames taking five days to be extinguished.
Images shared on social media channels following the latest attack show a large conflagration on the horizon, with thick plumes of black smoke spiralling skywards.
Roman Busargin, the governor of the Saratov region, said an “industrial enterprise” had been hit, without specifying which one.
Ukraine rarely acknowledges attacks it carries out outside of its internationally-recognised borders.