KYIV, Ukraine – In the crowded operating room, surgeons had made the long incision in the center of the boy’s chest, cutting through his breastbone to separate his rib cage and reach his heart.

Then the lights went out.

Generators were turned on to keep life support equipment running Wednesday night and nurses and surgical assistants were detained lanterns on the operating table, guiding the surgeons as they cut, working to save the boy’s life in near total darkness.

“So far we’ve been managing on our own,” said Borys Todurov, clinical director, the Heart Institute, in Kiev, Ukraine.

“But every hour is more difficult. There has been no water for several hours. We continue to do only emergency operations”.

In its increasingly destructive campaign to target Ukrainian civilians by cutting off electricity and running water, Russia hammered the Ukrainian population this week in a wave of rocket attacks that was one of the most disruptive in recent weeks.

Ukrainian engineers and emergency crews worked desperately on Thursday to restore services despite snow, freezing rain and blackouts.

And across the country, people have faced hardships.

While surgeons wore headlamps to work in the dark, miners were hauled out of the underground with hand winches.

High-rise residents carried buckets and water bottles up the stairs of buildings where elevators had stopped working, and shops and restaurants turned on generators or candles to keep going.

Though Ukrainians defied Russia’s efforts to weaken their resolve amid the worsening cold, millions were still without power Thursday night as persistent Russian missile attacks claimed more and more lives.

At least 10 people died on Wednesday, according to Ukrainian authorities.

After each missile attack, repairs have become more difficult, blackouts have lasted longer, and the danger to the population has increased.

“The situation is difficult throughout the country,” acknowledged Herman Galushchenko, Ukraine’s energy minister.

By 4 a.m., he said, engineers had managed to “unify the power system,” allowing power to be directed to critical infrastructure.

Wednesday’s dismissal, which injured scores of people, appears to be one of the most disturbing attacks in recent weeks.

Since the October 8 explosion at the Kerch Strait bridge, which connects the occupied Crimea peninsula with Russia, the Russian military has fired on 600 missiles against power plants, hydroelectric plants, pumping and water treatment stations, and high-voltage cables around nuclear power plants and critical substations that bring power to tens of millions of homes and businesses, according to Ukrainian officials.

Wednesday’s attacks put all of Ukraine’s nuclear power plants out of action for the first time, depriving the country of one of its most vital energy sources.

But the energy minister said authorities hoped the plants would be back up and running soon, “then the deficit would decrease.”

The Kremlin denied on Thursday that its attacks were directed against the civilian population. A spokesman, Dmitry Peskov, said that “we are talking about infrastructure targets that have a direct or indirect relation to Ukraine’s military potential,” according to Russian news agencies.

He added that the leadership of Ukraine “has every opportunity to bring the situation back to normal, has every opportunity to resolve the situation in such a way that the demands of the Russian side are met, and, accordingly, every opportunity to putend to suffering of the peaceful population”.

The President of Ukraine, Volodymyr Zelenskyhe rejected any suggestions for a truce or peace talks at this juncture, saying that Moscow’s war aims have not changed and that a lull in hostilities would only give the Russian military time to regroup after recent setbacks.

In mid-October, the president Vladimir Putin He said the attacks on nearly a dozen Ukrainian cities were in retaliation for the Kerch Bridge truck bomb, and since then the Russian military has increasingly attacked civilian infrastructure.

But the barrage of rocket attacks also reflected Russia’s persistent battlefield fighting, as its ground forces withdrew from thousands of square kilometers of northeastern Ukraine in September and then from a major southern city to November.

Seeking to consolidate its lines on the ground – even with poorly trained and recently mobilized recruits – the Russian military has resorted to long-range rocket attacks as a means of deflecting internal criticism and inflicting pain while on the defensive.

Ukraine has deployed its Western-supplied weapons against the attacks, while calling for more help.