The plant in the Bashkortostan region, some 1,500km from the Ukrainian border in the Ural Mountains, was operating without interruption, the head of the Bashkortostan region, Radiy Khabirov, said on the Telegram messaging app.

He added that both of the drones involved in the overnight strike were destroyed.

The Russian defence ministry said in its daily report that, in addition to the two drones downed over the Bashkortostan region, its defence systems destroyed 83 drones over seven other Russian regions.

The administration of the city of Sterlitamak, where the plant is located, said that all five workers inside were not injured.

There was no immediate comment from Ukraine.

Kyiv has stepped up long-range drone and missile strikes inside Russia, hitting oil refineries, depots and logistics hubs it says feed the Kremlin’s war machine.

Moscow calls the attacks terrorism, but Ukraine says they are legitimate self-defence in the war that Russia launched in February 2022.