“The enemy has organised a massive combined strike on the territory of the Russian regions,” the Two Majors war blogger said. Alexander Bogomaz, the governor of the Bryansk region in western Russia, said Ukraine had launched a major missile attack but did not say which missiles had been used.

Officials in several Russian regions, some hundreds of kilometres from the border, reported strikes overnight.

Ukrainian forces used missiles and drones on Tuesday to target sensitive military and energy sites across Russia.