Overnight Russian missile and drone strikes have caused power cuts in large parts of Ukraine's capital, Kyiv, and eight other regions.
Kyiv's authorities said power was later restored to more than 540,000 consumers in the city - but many households are still without electricity.
Twelve people were injured in the city, said Mayor Vitaliy Klitschko. In the southern Zaporizhzhia region, a seven-year-old boy was killed and seven others injured. Ten people were also injured in the central Cherkasy region.
Russia's defence ministry said its "massive" strike with high-precision weapons - including hypersonic missiles - targeted energy facilities used by Ukraine's "military-industrial complex".
Russia - which launched a full-scale invasion of Ukraine in 2022 - has escalated attacks on Ukrainian energy facilities as well as transport infrastructure as winter approaches.
Reacting to the latest Russian strikes, Ukrainian President Volodymyr Zelensky reiterated calls for allies to act decisively to "defend people from this terror".