Ukrainian President Volodymyr Zelensky has condemned as terrorism a Russian drone attack on a crowded passenger train that local officials say killed at least five people and injured several others. More than 200 people were on the train, officials said, when one of the carriages was hit by a drone and two other drones exploded nearby, in Ukraine's north-eastern Kharkiv region on Tuesday. Zelensky said 18 people were in the carriage at the time and there was no military justification in targeting civilians. Russia has not commented on the strike, but it has intensified drone and missile attacks on Ukraine's energy and transport infrastructure during the harshest winter in years. Elsewhere in Ukraine, the southern port city of Odesa was hit by dozens of drones and officials said three people were killed and dozens more wounded.

Russia has been exploiting Ukraine's harshest winter in years to pummel energy infrastructure across the country. Repeated strikes have crippled the power supply to major Ukrainian cities, leaving millions without heating or light as temperatures hover around -15C (5F) for the third week in a row. Electrical companies carry out round-the-clock repairs - only for their work to be undone at night, when Russian drone and missiles again damage power stations. In Kyiv, people were initially able to keep the cold at bay by using electric heaters or wrapping up warm. But the freezing temperatures have lasted weeks now, with no end in sight.