Ukraine fired a wave of drones at Russia overnight, sparking a blaze at an oil depot and "explosions" at a plant producing military aircraft, its army said yesterday.

Neither side has shown signs of deescalating since US President Donald Trump returned to office on Monday. The Republican has promised to bring a swift end to the nearly three-year war, but has not yet set out a plan for doing so.

In the western Voronezh region bordering Ukraine, Kyiv said it struck an oil depot near the town of Liski for the second time in less than a week, sparking another blaze at the facility.

"Tanks with fuel and lubricants used by the occupiers to supply Russian troops caught fire," the Ukrainian army said on Facebook.

The region's governor, Alexander Gusev, said the fire was caused by debris from a downed drone and that no-one was injured.

Ukraine also said it struck an aviation plant producing "combat aircraft" in the western Russian city of Smolensk, sparking "explosions".

The governor of the Smolensk region did not comment on the attack, saying only that falling debris from downed drones had sparked "roof fires".

In the Orenburg region bordering Kazakhstan, hundreds of kilometres from the frontline, authorities in the towns of Yasny and Komarovsky urged civilians to take cover in their nearest shelters due to the risk of a "drone attack".