A dozen other people were injured, some seriously, in the attack in the city of Sumy, which has come under increased bombardment since Ukraine’s offensive into Russia’s nearby Kursk region.

Ukraine's air force said on Thursday it had shot down all 42 drones and one of four missiles used by Russia during overnight attacks. Air defences went into operation in nine Ukrainian regions, the air force said in a statement on the Telegram messaging app nearly 31 months after Russia's full-scale invasion.

A senior Russian official visited Iran on Tuesday, likely to bolster missile supplies, experts said. His visit came days after a trip to North Korea.

President Vladimir Putin said on Thursday that the Russian military received around 140,000 drones in 2023 and that Moscow plans to increase this number tenfold in 2024.

A partial evacuation has been ordered in Russia's Tver region after a "massive" Ukrainian drone attack sparked a fire there, the local governor has said. Igor Rudenya said emergencies services in the town of Toropets were trying to "localise" the blaze caused by falling drone wreckage.

In 2023, the Russian army received about 140,000 drones of different types, according to Russian President Vladimir Putin. This year, Moscow is planning to produce 1.4 million, he claimed.