Ukraine has blasted Vladimir Putin for the latest "barbaric" airstrike on its two biggest cities just hours after trilateral peace negotiations got under way in Abu Dhabi.
A major missile and drone attack overnight in Kyiv and Kharkiv left at least 23 people injured while one person was killed in the capital.
Ukrainian president Volodymyr Zelensky says the attacks demonstrate that Putin is "not ready" to make peace.
Mr Zelensky stated the US must implement the additional air defences it agreed at the World Economic Forum in Davos and said: "The key is that Russia must be ready to end the war it started."
Ukraine's air force stated that 375 drones and 21 missiles were launched by Russia in the strikes, which took aim at key energy infrastructure sites and led to the loss of electricity and heat for much of Kyiv.
Kyiv Mayor Vitali Klitschko said the strikes caused fires in districts on both sides of the Dnipro River, which runs through the capital.
Since the New Year, Kyiv has suffered two major overnight attacks that struck off power and heating to hundreds of homes. On Friday night, emergency workers were trying to restore energy for residents as temperatures plunged to -13C.
In Kharkiv - Ukraine’s second-largest city in the northeast of the country, just 18 miles from the Russian border - Mayor Ihor Terekhov said 25 drones struck several districts over the course of two and two and half hours, injuring at least 11 people.
Ukrainian foreign minister Andrii Sybiha described the attacks after the first day of negotiations as "cynical", adding: “This barbaric attack once again proves that Putin’s place is not at the board of peace, but at the dock of the special tribunal.”
The talks involving Ukraine, Russia and the US in Abu Dhabi were continuing on Saturday and are the first trilateral discussions since Moscow launched its full-scale invasion in February 2022.
The big issue that threatens to scupper efforts to resolve the war through diplomacy remains the future of Ukraine’s eastern Donbas region, which contains the areas of Donetsk and Luhansk currently occupied by Russia. The Kremlin insists that having control of the Donbas is "a very important condition".
