KYIV, Ukraine — Utility crews worked through the dark night in snow and freezing rain to stabilize Ukraine’s battered energy grid on Thursday after another destructive wave of Russian missile strikes, restoring essential services like running water and heat in many parts of the country even as millions remained without power.
Ukrainians have expressed defiance in the face of Moscow’s unrelenting campaign to weaponize winter in an attempt to weaken their resolve and force Kyiv to capitulate even as Russia heaped new suffering on a war-weary nation.
Surgeons were forced to work by flashlight, thousands of miners had to be pulled from deep underground by manual winches and people across the country lugged buckets and bottles of water up flights of stairs in high-rise apartment buildings where the elevators had stopped running.
The State Border Service of Ukraine suspended operations at checkpoints on the borders with Hungary and Romania on Thursday because of power outages, and Ukraine’s national rail operator reported delays and disruptions across a network that has served as a resilient lifeline for the nation over nine months of war.
Families charged their phones, warmed up and gathered information at centers set up in towns and cities during extended power outages. The police in the capital, Kyiv, and in other cities stepped up patrols as the owners of shops and restaurants flipped on generators, or lit candles, and kept working.
“The situation is difficult throughout the country,” said Herman Galushchenko, Ukraine’s energy minister. But by 4 a.m., he said, engineers had managed to “unify the energy system,” allowing power to be directed to critical infrastructure facilities.
In Moldova, Ukraine’s western neighbor, whose Soviet-era electricity systems remain interconnected with Ukraine’s, the grid was largely back online after the country experienced “massive power outages,” the infrastructure minister said on Twitter. “We move on, stronger and victorious,” the minister, Andrei Spinu, wrote.
The barrage of Russian missiles on Wednesday killed at least 10 people and injured dozens, Ukrainian officials said, in what appeared to be one of the most disruptive attacks in weeks. Since Oct. 10, Russia has fired around 600 missiles at power plants, hydroelectric facilities, water pumping stations and treatment facilities, high-voltage cables around nuclear power stations and critical substations that bring power to tens of millions of homes and businesses, according to Ukrainian officials.
The campaign is taking a mounting toll. The strikes on Wednesday put all of Ukraine’s nuclear power plants offline for the first time, depriving the country of one of its most vital sources of energy.
“We expect that nuclear plants will start working by the evening, so the deficit will decrease,” Mr. Galushchenko said.
Gen. Valeriy Zaluzhnyi, the top commander of Ukraine’s Armed Forces, said Ukrainian air defenses shot down 51 of the 67 Russian cruise missiles fired on Wednesday and five of 10 drones.
President Volodymyr Zelensky, speaking Wednesday night at an emergency session of the United Nations Security Council, decried what he called a Russian campaign of terror.
“When the temperature outside drops below zero and tens of millions of people are left without electricity, heat and water as a result of Russian missiles hitting energy facilities,” he said, “that is an obvious crime against humanity.”
In an interview with the Financial Times published Thursday, Mr. Zelensky said Ukraine’s resolve to regain all of its territory would not be weakened by Russian attacks on its energy system.
In Kyiv, around one in four homes still had no electricity on Thursday afternoon, and more than half of the city’s residents had no running water, according to city officials. Service was gradually being restored, city officials said, and they said they were confident that the pumps that provide water to some three million residents would be restored by the end of the day.
Dmytro Saharuk, executive director of Ukraine’s largest private energy investor, DTEK, said power had been restored to about 30 percent of Kyiv’s residents but would only be available for about two or three hours per day as the system is restored. He said all of the city’s critical infrastructure had been restored.
Transit was suspended in the southern port city of Odesa on the Black Sea so that the limited energy supply could be directed to getting water running again. In the Lviv region in Ukraine’s west, where millions displaced from their homes by fighting, power and water have fled, services were largely restored.
The national energy utility, Ukrenergo, said that given the “significant amount of damage” and difficult working conditions, repairs in some regions may take longer than others.
“There is no reason to panic,” the utility said in a statement. Critical infrastructure would all be reconnected, it said.
Power was slowly coming back to the key southern city of Mykolaiv. By 9 p.m. local time, it had been restored in about half the city. The long avenues were eerie and deserted, with the streetlights off, and in many buildings a lone light burned somewhere inside, most likely a flashlight. But many people there didn’t seem that bent out of shape.
“They want us to suffer,” said Anhelina Peresunko, a manager at a hotel sitting in a lobby lit by flickering candles on Wednesday night when the power disappeared. “But I’m not worried. Not at all. We charge all our power banks and our phones. We are always preparing ourselves.”
Jeffrey Gettleman contributed from Mykolaiv.