Ukrainian drone attacks killed at least one person in southern Russia and caused damage to industrial sites, regional authorities said Wednesday morning. Saratov region Governor Roman Busargin said one person was killed and several others were injured in a Ukrainian strike.

Russia has been using small drones flown via fibre-optic cables ​to bypass Ukrainian defences and damage high-voltage electricity substations in the frontline northern Ukrainian region of Sumy, open-source analysis shows.

Russia has exploited Ukraine’s air-defence weaknesses with a heavy ballistic missile attack early on Saturday, killing six people.