Russian Strikes Leave Six Million in Ukraine Without Power

Kyiv, Ukraine—Ukraine said six million people remained without power on Saturday as it worked overtime to repair critical infrastructure damaged by Russian strikes in recent days and bolster the spirits of residents who are struggling without water and electricity as temperatures drop.

Ukrainian President Volodymyr Zelensky urged Ukrainians to limit their energy consumption in a video address late on Friday, saying that if a home or apartment currently has power it may well be left without it at any moment.

In a message to Ukrainians on Saturday, the day the country commemorates the 1932-33 Holodomor famine that killed some three million people, Mr.

Zelensky said Moscow was using tactics similar to those it used almost a century ago when Soviet leaders deprived Ukraine of food.“Once they wanted to destroy us with hunger, now with darkness and cold,” he said in a message on his Telegram channel. “We cannot be broken. Our fire won’t go out. We will conquer death again.”

Mr. Zelensky’s message comes after two days in which much of Kyiv has been without power and water for long stretches and residents have scrambled to procure supplies that will help them get through winter and stockpiles of basic items like candles and generators dwindle.

Russia has stepped up its missile barrages against Ukraine in recent weeks as it seeks to destroy key infrastructure and weaken Ukrainians’ resolve to keep supporting the country’s defense. Surveys show that the tactic hasn’t succeeded in turning the population against Mr. Zelensky and his government.

But it is unclear how long Russia can maintain the pace of attacks. The U.K.’s Defense Ministry on Saturday said Russia was likely removing nuclear warheads from aging cruise missiles for use against targets in Ukraine, further evidence that its stockpile of long-range missiles was low.

The ministry said recent open-source imagery showed the wreckage of an air-launched missile fired toward Ukraine was designed in the 1980s as a nuclear delivery system. It said warheads were likely being substituted with ballast and the missile could still cause some damage through its kinetic energy and unspent fuel.

“Whatever Russia’s intent, this improvisation highlights the level of depletion in Russia’s stock of long-range missiles“, the ministry said in a statement posted to Twitter.

As Ukraine fights to push back Russian forces still occupying vast areas of the country’s east and south, with particularly fierce battles continuing over the city of Bakhmut in the eastern Donbas region, Ukrainian officials say a network of resistance fighters continues to destabilize occupation officials and Russian military administrators in areas far from the front line.

Two Russian soldiers and a Ukrainian collaborator were killed by a car bomb in Russian-occupied Mariupol this week, said Petro Andriushchenko, an assistant to Mariupol’s exiled Ukrainian mayor.

“Minus one occupier is definitely great news for tonight,” he wrote in a post to Telegram.

Write to Matthew Luxmoore at matthew.luxmoore@wsj.com