According to official reports, at least five people have been injured in a Russian missile attack in the southern Ukrainian port city of Odessa.
A 15-year-old boy was among the victims, Odessa's mayor Hennadii Trukhanov announced on Friday. Although two missiles had been shot down by the air defence, debris had fallen onto streets and buildings.
In his evening video address, Ukrainian President Volodymyr Zelensky once again insisted on more international help with air defence.
"The enemy's main target in this missile terror is our energy sector," said Zelensky, referring to the attacks of recent days, which had again increasingly targeted Ukrainian energy facilities.
Ukraine on Friday once again reported severe damage to the country's energy infrastructure following massive Russian attacks that triggered a nationwide air raid alert.
Power generation plants were particularly targeted by the Russiain missiles and drones, the Energy Ministry in Kiev said, adding that emergency services were working to mitigate the impact of the airstrikes. The Dnipropetrovsk region and other regions were affected.
Hydroelectric and thermal power stations in the west and centre of Ukraine were damaged, the energy supplier Ukrenergo announced on Friday.
The Ukrainian air defence reported in the morning that 84 of a total 99 Russian targets had been shot down in the air. Russia made extensive use of drones, missiles and cruise missiles, the report stated.
In western Ukraine, the Ivano-Frankivsk and Khmelnytskyi regions reported explosions following the airstrikes.
The Polish armed forces said that fighter jets from Poland's air force and allies had been scrambled due to the attacks. This has happened in the past amid violent airstrikes on Ukraine. After about three hours in the morning the action was over, according to the army.
Russia invaded Ukraine more than two years ago, but it has recently intensified its attacks on the country's energy infrastructure, hoping to demoralize Ukrainians.
Ukrenergo said scheduled power cuts are currently necessary in the Kharkiv region. The power supply is also at risk in the Odessa and Khmelnytskyi regions. Ukraine currently imports electricity from five neighbouring countries to the west.
Meanwhile across the border in Russia, one man has been killed and two people were injured in a Ukrainian drone attack on the city of Belgorod, local authorities said on Friday.
The wife of the man who was killed was taken to hospital with a traumatic brain injury and burns, Belgorod Governor Vyacheslav Gladkov said on Telegram. The windows and balconies of five flats as well as a car were damaged in the attack, he added.
A video showed a drone crashing into a high-rise building. Dpa was not able to independently verify the footage.
In the United States, experts from the Institute for the Study of War (ISW) have confirmed that Russia has made territorial gains in its war against Ukraine.
The Russian armed forces have captured an area of 505 square kilometres since the beginning of offensive operations in October, the ISW reported in its latest analysis, published on Thursday.
Ukraine is still preventing Russia from making major tactical gains along the entire front line, the ISW says. However it warns that Russia's "opportunities to exploit Ukrainian vulnerabilities will widen as materiel shortages persist and as Ukraine continues to grapple with how to address manpower challenges."
Earlier, Ukrainian President Volodymyr Zelensky had warned of a possible new major Russian offensive in early summer. The ISW believes Russia will maintain its current offensive tempo despite difficult weather conditions.
The ISW experts emphasize the importance of Western help in stopping the Russian advance. They also point out that the Ukrainian air defence shield was becoming weaker and weaker.
Also on Friday, Russia and Ukraine again exchanged bodies of soldiers killed in the conflict.
Kiev received 121 bodies in the exchange, the Ukrainian Coordination Headquarters for the Treatment of Prisoners of War announced on Telegram. The Russian side received 29 bodies, according to parliamentary deputy Shamsail Saraliyev in Moscow.