Russian missiles killed at least one person and damaged energy infrastructure across Ukraine, according to officials, who reported a massive Christmas attack.
Air raid sirens rang out over Ukraine on Wednesday morning, while the air force reported Russian Kalibr cruise missiles had been launched from the Black Sea.
Ukraine faces its toughest winter of the almost three-year war as Moscow steps up its aerial bombardment and its troops advance on the frontlines in the east.
On Wednesday morning, the governor of Kherson region reported that one person had been killed three others injured over the last 24 hours.
In Dnipropetrovsk region, where winter temperatures have hovered around the freezing point, the governor said Russia was taking aim at the power grid.
"The enemy is trying to destroy the region's power system," Lysak wrote on Telegram. "Stay in a safe place until the air alert is lifted. Take care of yourself!"
A search and rescue operation after strikes on Christmas Eve found a 43-year-old man had been killed and 17 others wounded, Dnipropetrovsk Governor Sergiy Lysak said.
A "massive missile attack" also pummelled Ukraine's northeastern city of Kharkiv early Wednesday, according to Mayor Igor Terekhov.
"Kharkiv is under a massive missile attack. A series of explosions were heard in the city and there are still ballistic missiles heading towards the city," Terekhov wrote on Telegram.
The regional governor counted seven Russian strikes and said at least three people were injured.
Scramble for upper hand
Since the start of the war in February 2022, Russia has severely damaged Ukraine's power grid by repeatedly bombing it, causing regular power cuts.
Ukraine has regularly appealed to its allies for more robust air defence systems to thwart Russian attacks on the war-battered country's power system.
Last month, Washington cleared Ukraine to use long-range American missiles against military targets inside Russia, prompting fiery rhetoric and vows of retaliation from Moscow.
In November, Russia launched almost 200 missiles and drones targeting Ukraine's energy grid, with President Volodymyr Zelensky alleging "cluster munitions" were fired in what he called a "despicable escalation" almost three years into the war.
Both sides are scrambling to gain an upper hand ahead of Donald Trump being inaugurated as US president in January.
The Republican has promised to bring a swift end to the conflict, without proposing any concrete terms for a ceasefire or peace deal.
Moscow's army claims to have seized more than 190 Ukrainian settlements this year, with Kyiv struggling to hold the line in the face of manpower and ammunition shortages.
Russia's defence ministry said Wednesday its forces had shot down 59 Ukrainian drones overnight.