The attack came on the third day of a planned prisoner swap between Russia and Ukraine, the only tangible outcome from peace talks in Istanbul earlier this month.

The massive missile and drone attack across Ukraine followed large strikes the night before, and casts more doubt on the U.S.-brokered peace process.

Officials say a massive Russian attack of drones and missiles targeted the Ukrainian capital and other regions early Sunday in the country for a second consecutive night, killing at least 12 people and injuring dozens.