Ukraine has launched its second major drone attack in a week against Russian oil refineries hundreds of miles from its borders.

Ukrainian drones hit an oil refinery 250 miles east of Moscow in a huge wave of attacks on Russian power plants, say military sources. A large fire exploded at the refinery in Kstovo city in the Nizhny Novgorod region following the attack, the Ukrainian military said, adding it was assessing the scale of damage there.