Parts made by more than a dozen US and Western companies were found inside a single Iranian drone downed in Ukraine last fall, according to a Ukrainian intelligence assessment obtained exclusively by CNN.

Air raid sirens sounded shortly before midnight as the latest in a wave of attacks by Russia over the New Year period began.

Ukrainian officials say cities across the country are targeted in several waves of strikes.

Ex-deputy PM Dmitry Rogozin was hurt in an attack on a hotel in Russian-occupied Donetsk.