Russia claimed on Friday that it had destroyed 11 Ukrainian drones overnight, though one UAV dropped explosives on a substation, cutting the local power supply, a regional governor said.

“Eleven Ukrainian unmanned aerial vehicles were destroyed by air defence systems on duty, one of them over the territory of Kaluga region and 10 over Kursk region,” Russia’s defence ministry said on the messaging platform Telegram.

Kursk governor Roman Starovoyt said that the region bordering eastern Ukraine was “massively attacked” by Ukrainian UAVs.

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In Belaya village, less than 25 kilometres (16 miles) from the border, “a Ukrainian drone dropped two explosive devices on a substation”, he said on Telegram.

“One of the transformers caught fire. Five settlements and a hospital were cut off from power supply. Fire crews rushed to the scene,” he added.

“Power will be restored as soon as it is safe to do so.”

The governor warned citizens that “due to the danger of self-destruction of downed UAVs, it is forbidden to touch their debris, approach them or take photographs”.

Russia earlier said it had destroyed two Ukrainian drones on Thursday evening over the neighbouring Belgorod region.

The defence ministry said the first drone was “thwarted” at about 5:00pm (1400 GMT), while a second was brought down around four hours later.

The Belgorod and Kursk regions, south of Moscow, border eastern Ukraine. Kaluga region is closer to the Russian capital.

Since Ukraine launched its counter-offensive in early June, Russia has weathered waves of drone attacks that have sporadically damaged buildings, including in Moscow.