The attacks have caused widespread blackouts, and cut off water supplies and heating to civilians when temperatures in some areas dropped to minus five degrees Celsius (41 degrees Fahrenheit).
Authorities have scheduled power cuts several times a day to keep essential infrastructure working.
In eastern Ukraine, where fighting is still raging, the governor of the Lugansk region, Sergei Gaidai, said fighting was heavy, “because the Russians had time to prepare”. He said that the Ukrainian army was still moving slowly.
Ukraine’s president said the situation was also difficult in Bakhmut, in the neighboring Donetsk region, which Russian forces have been trying to capture since the summer.
On Saturday, the governor of the southern region of Mykolaiv, Vitaly Kim, urged citizens to “endure” the power outages.
Putin told German Chancellor Olaf Scholz on Friday that the Russian strikes, which have destroyed half of the Ukrainian energy system, were an “inevitable response to Kyiv’s provocative attacks on Russia’s civilian infrastructure”.
He was referring specifically to an attack in October on a bridge linking Moscow-annexed Crimea to the Russian mainland.
Putin accused the West of pursuing “disastrous” policies in Ukraine, the Kremlin said, adding that Western political and financial aid meant Kyiv “completely rejects the idea of any talks”.
Ukraine’s President Volodymyr Zelensky has ruled out talks with Russia while Putin is in power after the Kremlin claimed annexation of several Ukrainian territories.
The Kremlin also said on Saturday that Putin would visit the Donbass region of eastern Ukraine “in due course”, which he claimed would be his last visit. But Peskov gave no indication of when that might happen.