Russia's fourth-largest oil refinery in Ryazan was forced to suspend operations at its main crude distillation unit on Wednesday following a Ukrainian drone attack, two industry sources told Reuters on Friday.

The AVT-4 unit was urgently shut down after a fire caused by a drone strike. Additionally, related operations—reforming, vacuum gas oil hydrotreating, and catalytic cracking—were suspended, leading to a reduction in refining volumes at the facility. The Rosneft-owned refinery continues to operate, but at a limited capacity.

Attacks on Russian energy facilities have increased amid a lack of progress in peace talks brokered by US President Donald Trump.