STORY: Firefighters battled a fire at a thermal power plant in Ukraine's Kharkiv on Sunday, following Russian missile strikes that caused widespread blackouts.
Ukrainian officials have accused retreating Russian forces of attacking civilian infrastructure in retaliation to the weekend offensive by Ukrainian troops which drove Russia out of its key stronghold in the Kharkiv region.
Local authorities said at least one duty officer was killed in the strikes.
"No military facilities, the goal is to deprive people of light & heat," Ukraine President Volodymyr Zelenskiy tweeted late on Sunday.
He said the attacks caused a total blackout in the Kharkiv and Donetsk regions, and partial blackouts in several other places.
Moscow denies its forces deliberately target civilians in what it calls its “special operation”.
The Russian strikes came after Ukrainian's army said its forces had made more gains in the Kharkiv region.
Video released on social media by a district mayor shows him and Ukrainian soldiers being embraced by some residents, as they shout “glory to Ukraine”.
The video is said to be taken in a village near the Russian border, about 27 miles north of Kharkiv, though Reuters is unable to verify it.
Ukraine says its forces have regained more than 1,100 square miles since the start of this month, releasing images of Russian equipment that has now fallen into their hands.
Defence Minister Olkeksii Reznikov struck a cautious tone, telling the Financial Times that Ukrainian forces could be encircled by fresh Russian troops if they advance too far.
Still, it’s the worst defeat for Russia’s forces in the war since they were repelled from the outskirts of Kyiv in March.
Reznikov said the offensive went far better than expected, saying, “It's a sign that Russia can be defeated.”
Reuters / 107 Separate Brigade of the Bukovyna Territorial Defence Forces / Twitter/ZelenskyyUa / Territorial Defence of the Ukrainian Armed Forces/Handout via REUTERS / UKRAINIAN ARMED FORCES / Telegram @V_Zelenskiy_official / Facebook/Vyacheslav Zadorenko