Vladimir Putin has vowed to continue attacking Ukraine's energy infrastructure despite millions being left without electricity or water.
"Yes, we do that. But who started it?" the Russian president said at an awards ceremony in the Kremlin.
He said that criticism of Russian strikes would "not interfere with our combat missions".
Moscow has been battering Ukraine's power grid since 10 October, following a string of heavy military defeats.
Some Western leaders have called the strategy a war crime, because of the huge amount of damage caused to civilian infrastructure.
But President Putin said that growing global criticism would not stop the strikes.
"There's a lot of noise about our strikes on the energy infrastructure of a neighbouring country. Yes, we do that. But who started it?" he said to recipients of state awards, including the "Hero of Russia" medal.
He said the strikes were in response to a blast on the Russian bridge to annexed Crimea on 8 October. He also accused Ukraine of blowing up power lines from the Kursk nuclear power plant and of cutting water supply to Donetsk in eastern Ukraine.
"Not supplying water to a city of more than a million people is an act of genocide," Mr Putin said, accusing the West of "complete silence" on these claims and of bias against Russia.
Ukrainian Prosecutor-General Andriy Kostin said last month that Russia's attacks on Ukrainian energy infrastructure amount to genocide.
The Russian president said that when Moscow responds to Ukrainian aggression "there is uproar and clamour spreading through the whole universe".
Ukraine is now seeing snow and sub-zero temperatures in many regions, and millions are without electricity and running water, raising fears people may die of hypothermia.
The country switched to emergency shutdowns to stabilise its power grid after a fresh wave of Russian missile attacks on Monday.
Experts have told the BBC that Russia's tactic of hitting energy infrastructure is most likely designed to demoralise and terrorise the population, rather than gain any concrete military advantage - a move that would violate international law.
Moscow has repeatedly denied the allegations.
Frank Gardner looks at what lies ahead as winter arrives in Ukraine.
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