Russia has reportedly carried out "one of its biggest attacks" during its ongoing war on Ukraine, targeting vital energy infrastructures across the ex-Soviet republic.
The attack saw the Russian military launching scores of missiles against Ukraine, Reuters reported on Friday.
The attacks caused three deaths in the central Ukrainian city of Kryvyi Rih, and killed another person in the city of Kherson in the south, the agency said, citing "Ukrainian officials."
Also on Friday, Russian-installed officials in the occupied eastern Ukraine said 12 people had died by Ukrainian shelling.
Ukraine's army claimed that it had intercepted and brought down 60 of the 76 incoming Russian missiles.
Ukrainian Energy Minister German Galushchenko said the projectiles had struck at least nine power-generating facilities throughout the country.
The attacks forced Kiev to start "implementing emergency blackouts nationwide," the news agency reported, citing Ukrainian officials.
In Kharkiv, Ukraine's second-largest city, the missile barrages knocked out electricity, heating, and running water, it added.
The Interfax Ukraine news agency cited regional governor Oleh Synehubov as saying, though, that 55% of the city's power had been restored following the attacks.
Russia's war on Ukraine started in late February with Moscow saying that it was aimed at defending the pro-Russian population in the eastern Ukrainian regions of Luhansk and Donetsk against persecution by Kiev.
Ever since the beginning of the war, Ukraine's Western allies, led by the US, have been pumping the ex-Soviet Republic full of advanced weapons and slapping Russia with a slew of sanctions, steps Moscow says will only prolong the conflict.
So far during the military conflict, Moscow has seized around a fifth of Ukraine's expanse in its south and east. It has conditioned negotiations on a possible end to the military campaign on Ukraine's recognition of Russian rule over the seized territories.