Condemnation of Russia is mounting over its repeated attacks on Ukraine's energy infrastructure nine months after the start of the Russian invasion of the country.
Moscow again carried out attacks on Wednesday against the capital Kyiv and other Ukrainian cities, targeting energy infrastructure. Ukraine says Russia fired 70 missiles on the day, killing 10 people and injuring 36.
Ukraine's state-run utility Ukrenergo announced nationwide 24-hour emergency power cuts later in the day.
The country's president, Volodymyr Zelenskyy, addressed an emergency meeting of the United Nations Security Council via video link on Wednesday.
He condemned the attacks as "energy terror," saying that when the outside temperature is below zero, leaving many people without electricity and heat is a crime against humanity.
Norway's UN ambassador, Mona Juul, said Russia's aim "seems to be to terrorize the population."
US Assistant Secretary for Energy Resources Geoffrey Pyatt said at a ceremony in Washington on Wednesday that Russia is using its attacks on Ukraine's energy infrastructure to cast the country into darkness.
The European Parliament on Wednesday adopted a resolution to declare Russia a state sponsor of terrorism. It said the deliberate attacks and atrocities against civilians in Ukraine and the destruction of civilian infrastructure amount to acts of terror and war crimes.
Russia is believed to have moved some of its forces to fronts in Ukraine's east. They are part of the troops that were forced to leave the southern key area of Kherson.
Britain's defense ministry said on Thursday that Russia has likely redeployed major elements of its airborne forces to the east.
It said some elite airborne units dedicated to defending Kherson will likely be allocated to sectors deemed especially important. It added that their tasks can include supporting the defense of the Kremina-Svatove area in the Luhansk region or reinforcing offensive operations against Bakhmut in the Donetsk region.