Russian forces carried out missile and drone attacks across Ukraine on Friday, targeting the capital Kyiv, Kharkiv in the north, Odesa in the south, and the central city of Kryvih Rih.
Strikes on Ukrainian cities have intensified this week as Russia targets the country’s civilian infrastructure.
Power was down in Kharkiv and blasts were reported in north-eastern Kyiv.
Officials warned of potential casualties after a residential building was hit in Kryvih Rih.
Several other cities were also hit as alerts were put out across Ukraine. Vitaliy Kim, the mayor of the southern city of Mykolaiv, said as many as 60 missiles were thought to have been fired.
The governor of Sumy, a region close to Ukraine’s northern border with Russia, said power there was also out.
Kyiv Mayor Vitaliy Klitschko appealed to people not to leave shelters.
Millions of Ukrainians have gone without power as winter bites in Ukraine. UN human rights commissioner Volker Turk warned on Thursday that further attacks on power facilities could “lead to a further serious deterioration in the humanitarian situation and spark more displacement”.
Civilians have already been killed this week in Russian strikes. Two people died in shelling in the southern city of Kherson on Thursday.
US President Joe Biden is reportedly finalizing plans to send Patriot air defense missiles to Ukraine, after months of requests from Kyiv.