Officials say Ukraine was under an ongoing Russian ballistic missile and drone attack early Friday that wounded at least three people.

The attack on Friday, which killed at least four people in the capital, came two days after Russia vowed retaliation for an audacious drone assault on its strategic bomber bases.

Russia's Defence Ministry said on Friday that its forces had carried out a massive and successful strike on military and military-related targets in Ukraine overnight in response to what it called Ukrainian "terrorist acts" against Russia.