Russia reportedly launched large-scale drone and missile strikes on Ukraine's capital and other parts of the country early on Friday.
At least three people were killed and 49 injured in the strikes, according to Ukraine's President Volodymyr Zelensky.
The aerial raids targeted the capital, Kyiv, as well as the city of Lutsk and the Ternopil region in the north-west of the country.
Russia's defence ministry said the strikes were in response to "terrorist acts by the Kyiv regime", adding that it had targeted military sites.