The Russian-installed administration of Kherson blamed the outage on Ukraine, accusing it of attacking the Kakhovka hydroelectric dam.
The Russian-installed administration in Ukraine’s Kherson region has said that Kherson city lost water and power supplies after what it called an act of “sabotage”.
In a statement on Telegram, the Russian-installed administration of Kherson said a “terrorist attack” damaged three power lines in the region.
It said that the attack had been carried out by Ukraine, though it provided no evidence.
The outages are a “result of an attack organised by the Ukrainian side on the Berislav-Kakhovka highway that saw three concrete poles of high-voltage power lines damaged,” it said.
It is the first time that Kherson – which fell to Russian forces within days of Moscow’s invasion of Ukraine in February – has seen such a power cut.
Kherson is one of four regions that Russian President Vladimir Putin illegally annexed last month.
Russian state-owned news agency TASS quoted Kherson’s Moscow-appointed governor Vladimir Saldo as saying that there were plans for the city’s power supply to be restored by the end of the day.
Energy specialists were working to “quickly” resolve the issue, the Russian-backed authorities said as they called on people to “remain calm”.
TASS separately cited emergency services in the region as saying that 10 settlements, including Kherson city, which had a pre-war population of 280,000, had been left without electricity.
Russian officials have in recent weeks repeatedly warned civilians to leave Kherson, amid what they say are preparations for a Ukrainian offensive against the city, the only regional capital that Russia has captured since invading Ukraine on February 24.
News of the outage followed reports that the Kakhovka dam in the Russian-controlled region of Kherson was “damaged” by a Ukrainian strike.
“Today at 10:00 (08:00 GMT) there was a hit of six HIMARS rockets. Air defence units shot down five missiles, one hit a lock of the Kakhovka dam, which was damaged,” Russian news agencies quoted local emergency services as saying.
The RIA Novosti news agency quoted a local Moscow-backed official saying the damage was not “critical”.
The Kakhovka hydroelectric dam in southern Ukraine was captured by Moscow’s forces at the start of their offensive. It supplies Russian-annexed Crimea with water.
Both warring sides have been trading accusations over the Russian-held dam for weeks, Al Jazeera’s Harry Fawcett said.
“Ukrainians have been saying that the Russians have mined it and intended to blow it, while Russia said that Ukrainian forces were planning to fire a missile at it,” Fawcett said, reporting from Kyiv.
But if the dam was to be breached, Fawcett said, it would be a major catastrophe for both sides, “so there are still a lot of doubts as to whether either one would really want to do it”.
The dam holds back 19 million cubic metres of water and it is located at a short distance from Kherson, Fawcett said.
Ukraine has been warning in recent weeks that Moscow’s forces intended to blow up the strategic facility to cause flooding.
Russian strikes over the past month have destroyed around a third of Ukraine’s power stations and the government has urged Ukrainians to conserve electricity as much as possible.
But until now, Ukraine had only rarely struck Russian-held civilian energy infrastructure in territory annexed by Moscow, preferring to target Russian army supply lines.
Saldo said the dam’s destruction would lead to flooding of the left bank of the Dnieper River.
Ukrainian President Volodymyr Zelenskyy said last month that Russian forces had mined the Kakhovka hydroelectric power plant with the intent of blowing it up.
Its destruction could cause flash flooding for hundreds of thousands of people, he warned.
He said cutting water supplies to the south could also impact the cooling systems of the Zaporizhzhia nuclear power plant, Europe’s largest.
Al Jazeera and news agencies