Russia launched a drone strike on the Ukrainian capital Kyiv early on Wednesday, wounding at least six people and damaging buildings in two districts, city officials said. Explosions boomed across the morning sky as Ukraine's air force warned of drones approaching the city and Mayor Vitali Klitschko said air defences were repelling an enemy attack.

President Volodymyr Zelensky added that the Russian army also strikes settlements close to the front line with guided aerial bombs every day.

Russia on Saturday vowed to retaliate after it accused Ukraine of firing U.S.-supplied ATACMS missiles at the border region of Belgorod the previous day. Outgoing U.S. President Joe Biden authorized Kyiv to use the long-range weapons against Russia last year,