The attacks began shortly after midnight, targeted several regions, and lasted for several hours.
The temperature in Kyiv has been around minus 20 degrees Celsius overnight. Several projectiles have hit high-rise buildings and caused fires. Authorities are reporting injuries in several parts of the country, but initially no deaths.
The Ukrainian government states that it was a relatively large Russian attack wave, with more than 70 missiles and 450 attack drones.
Heat turned off
In the heavily besieged city of Kharkiv, next to the national border and the front line in the northeast, Governor Oleh Synyehubov reports attacks on the power grid aimed at causing the greatest possible destruction "and leaving the city without heat in severe cold."
Power was cut off to hundreds of households in Kharkiv to prevent a major outage. It has been even colder there than in Kyiv, where a thousand buildings are without power. From other parts of the country, there are reports of thousands of households without power and in some cases entire small towns.
"More important for Russia"
The privately owned electricity giant DTEK describes last night's attack as the most powerful against Ukraine's electricity grid so far this year.
"Taking advantage of the coldest winter days to terrorize people is more important to Russia than diplomacy," Ukrainian President Volodymyr Zelenskyy wrote on social media.
Neighboring Poland scrambled fighter jets near the Ukrainian border. The NATO country has acted several times before when Russian projectiles have flown into or through Polish airspace.
Said to have promised a ceasefire
The attacks come as Ukraine and invading Russia are set to meet for follow-up peace talks on Wednesday. An initial round of talks has been held with the United States, but they have yet to lead to any apparent changes in the fighting.
Last Thursday, US President Donald Trump announced that Russia had agreed to a short ceasefire over the weekend - as forecasts showed severe winter cold in both countries - but in Ukraine it was then reported that the attacks continued much as before.
Ahead of Wednesday's continued negotiations in the United Arab Emirates, the major stumbling block is reported to remain Russia's claim to the entire Donbas region in eastern Ukraine.
