Ukraine introduced emergency power cuts in six regions amid what authorities described as a "massive" Russian missile strike, the national grid operator said on Wednesday.
Kyiv's air force had warned of numerous groups of missiles launched by Russia amid a nationwide air-raid alert, but there were no immediate reports of damage.
In a statement, Ukrenergo said it had introduced the power cuts in the Kharkiv, Sumy, Poltava, Zaporizhzhia, Dnipropetrovsk and Kirovohrad regions.
Separately, Ukrainian energy minister German Galushchenko said on social media that "preventative measures" involving the distribution system were also in force.
Russia has carried out regular air strikes on Ukraine's energy grid as its ground forces press ahead on the battlefield in the Kremlin's three-year-old invasion.
Shooting at Australia's Bondi Beach kills 12
Police hold person of interest after Brown University shooting leaves two dead
Hamas says Israel's killing of senior commander threatens ceasefire
Ukraine's Zelenskyy ditches NATO ambition ahead of peace talks
Thailand declares curfew along coast as Cambodia border fighting spreads
