KHERSON, Ukraine — A salvo of missiles struck the recently liberated city of Kherson for the second day Friday in a marked escalation of attacks since Russia withdrew from the city two weeks ago following an eight-month occupation.

The barrages come as Russia has stepped up bombardment of Ukraine’s power grid and other critical civilian infrastructure in a bid to tighten the screws on Kyiv. Officials estimate that around 50% of Ukraine’s energy facilities have been damaged in the recent strikes.

European officials are scrambling to help Ukraine stay warm and keep functioning through the bitter winter months, pledging Friday to send more support that will mitigate the Russian military’s efforts to turn off the heat and lights.

France is sending 100 high-powered generators to Ukraine to help people get through the coming months, French Foreign Minister Catherine Colonna said Friday.

She said Russia is “weaponizing” winter and plunging Ukraine’s civilian population into hardship.

British Foreign Secretary James Cleverly, arriving Friday on a visit to Kyiv, said a promised air-defense package, which Britain valued at $60 million, would help Ukraine defend itself against Russia’s bombardments.

“Words are not enough. Words won’t keep the lights on this winter. Words won’t defend against Russian missiles,” Cleverly said in a tweet about the military aid.

The package also includes 24 ambulances and 11 other emergency vehicles, some of them armored.

“As winter sets in, Russia is continuing to try and break Ukrainian resolve through its brutal attacks on civilians, hospitals and energy infrastructure,” Cleverly said.

Russian officials have claimed they are hitting legitimate targets. But the U.N. High Commissioner for Human Rights on Friday expressed his shock at the depth of civilian suffering caused by the bombing, amid broader allegations of abuses.

“Millions are being plunged into extreme hardship and appalling conditions of life by these strikes,” Volker Turk said in a statement Friday. “Taken as a whole, this raises serious problems under international humanitarian law, which requires a concrete and direct military advantage for each object attacked.”

The head of the national energy utility offered some hope Friday, announcing that all three nuclear power plants under Ukrainian control are back online and will soon be producing energy at normal capacity after Russian attacks Wednesday triggered emergency protections at the facilities and required a halt to production.

“Now the energy system is fully integrated; all regions are connected,” said Volodymyr Kudrytskyi, chief executive of Ukrenergo, the national utility.

He added that utility crews are prepared to react to further Russian attacks but urged consumers to save electricity.

On Friday morning, electricity had been restored to meet about 70% of the country’s needs, but rolling blackouts remained in place, Ukrenergo said in a statement posted on the Telegram messaging app.

The Ukrainian governor of Kherson, Yaroslav Yanushevych, said Friday that Russian shelling killed 10 civilians and wounded 54 others the previous day, with two neighborhoods in the city of Kherson coming “under massive artillery fire.”

Russian shelling of parts of the Kherson region recently retaken by Kyiv compelled authorities to transfer hospital patients to other areas, Yanushevych said.

Some children were taken to the southern city of Mykolaiv, and some psychiatric patients went to the Black Sea port of Odesa, which is also under Ukrainian control, Yanushevych wrote on Telegram.

“I remind you that all residents of Kherson who wish to evacuate to safer regions of Ukraine can contact the regional authorities,” he said.

Soldiers in the region had warned that Kherson would face intensified strikes as Russian troops dig in across the Dnieper River.

Scores of people were injured in the strikes that hit residential and commercial buildings. The attacks wrought destruction on some residential neighborhoods not previously hit in the war, which has just entered its 10th month.

The New York Times contributed.