Two Rosneft-owned oil refineries in the cities of Syzran and Saratov have suspended processing following Ukrainian drone attacks over the past week, three industry sources told Reuters on Wednesday.

The sources said the Syzran plant paused operations on Tuesday, while the Saratov refinery halted work last Friday. Both facilities have repeatedly come under attack since the full-scale invasion of Ukraine in February 2022.

At the Syzran refinery, sources said the main CDU-6 crude distillation unit was damaged in a drone strike. The unit, which accounts for 71% of the plant's processing capacity, could take at least a month to repair, they added.

The refinery's second crude distillation unit, accounting for the other 29% of production capacity, was already undergoing maintenance after an attack in July.

Sources said the Saratov refinery has been shut down for several weeks following earlier strikes and was on the verge of restarting operations when it was attacked late last week.

Both refineries have a combined processing capacity of 290,000 barrels of oil per day.

Ukraine has been carrying out a far-reaching drone strike campaign against Russian oil refineries and fuel infrastructure since the spring, saying its goal is to raise the costs of the war for the Kremlin.

The near-nightly attacks have led to nationwide fuel shortages since June, prompting authorities to introduce rationing measures in some parts of Russia and across annexed Crimea.

U.S. President Donald Trump has recently blamed Ukraine's strikes for the surging cost of diesel across the globe and called on both Moscow and Kyiv to halt their attacks on energy infrastructure. However, neither side of the conflict has indicated that it's ready to agree to Trump's ceasefire request.

Reuters contributed reporting.