June 6 (UPI) — A major hydroelectric dam in Russia-occupied southern Ukraine was destroyed early Tuesday, forcing thousands of residents in the area to evacuate and raising fears over the safety of a nearby nuclear power plant.

Ukraine is blaming the Kremlin for blowing up the Kakhovskaya Hydro Electric Power Plant dam on the Dnipro River in Nova Kakhovka. Russia’s foreign ministry has published a statement denying responsibility and accusing Ukraine of “sabotage.” It said it will initiate a discussion on the “terrorist act” at the United Nations Security Council.

Russia-appointed Nova Kakhovka Mayor Vladimir Leontyev said the scale of destruction is “very serious” and that reconstruction will be a massive undertaking, Russian news agency TASS reported, while noting that Ukraine has been shelling the city.

Ukraine hydro power company Ukrhydroenergo said the breach in the dam was caused by a detonation in the engine room early Tuesday. By 9 a.m., the water level of the Kakhovka Reservoir had greatly decreased and the evacuation of the nearby population had begun.

Ukraine’s Southern Occupation Command blamed Russian troops for blowing up the dam, while warning in a statement that flooding in the region was likely.

Kyiv’s Ministry of Defense said Russian troops blew the dam “in a panic.”

Ten villages on the right bank of the Dnipro River and parts of the southern city of Kherson have been ordered to evacuate, Ukraine’s interior ministry said in a statement as water levels in the “danger zone” continue to rise.

Kherson region governor, Oleksandr Prokudin, said about 16,000 people are in the so-called critical zone on the right bank of the Kherson region.

“All elders and heads of communities have been informed and are gathering the population at designated collection points,” he said.

Those told to evacuate are being advised to turn off all electrical appliances, take documents with them and use information only from official Ukrainian sources as “the enemy is trying to spread misinformation, to remove responsibility for another crime,” the ministry said.

Serhiy Kruk, head of the State Emergency Service of Ukraine, said rescuers have been dispatched to southern Ukraine, along with high-terrain vehicles, boats, generators, mobile water treatment plants and other equipment.

As of 9 p.m., more than 1,360 people in the Kherson region were evacuated and the water level had risen by about 10 feet. Twenty-three settlements were flooded, the interior ministry said in an update.

Ukrainian President Volodymyr Zelensky said on Twitter he has convened the National Security and Defense Council. He also published drone aerial footage of the destroyed dam, showing the Dnipro River streaming through the large breach.

He blamed the dam’s destruction on “Russian terrorists” and said it was proof that they must be expelled from every corner of Ukraine.

“Not a single meter should be left to them, because they use every meter for terror,” he said. “It’s only Ukraine’s victory that will return security.”

“That victory will come.”

Russian terrorists. The destruction of the Kakhovka hydroelectric power plant dam only confirms for the whole world that they must be expelled from every corner of Ukrainian land. Not a single meter should be left to them, because they use every meter for terror. It’s only… pic.twitter.com/ErBog1gRhH— Володимир Зеленський (@ZelenskyyUa) June 6, 2023

Dmytro Kuleba, Ukraine’s foreign minister, described the dam destruction as “probably Europe’s largest technological disaster in decades.”

“This is a heinous war crime. The only way to stop Russia, the greatest terrorist of the 21st century, is to kick it out of Ukraine,” he tweeted.

Andriy Yermak, head of the president’s office, called it “ecocide.”

“The Russians will be responsible for the possible deprivation of drinking water for people in the south of Kherson region and Crimea, the possible destruction of some settlements and the biosphere,” he said.

The reservoir, among other functions, supplies water for turbine capacitors and safety systems at the nearby Zaporizhzhia Nuclear Power Plant, which has been occupied by Russia since early in the war and has repeatedly come under attack.

Ukraine’s nuclear power company, Energoatom, said the destruction of the dam is “an additional threat.”

“Currently, the power plant’s cooling pond is filled,” it said.

The International Atomic Energy Agency, the United Nations nuclear watchdog, said it is aware of reports of damage at the dam and experts at the nearby nuclear plant are closely monitoring the situation.

“No immediate nuclear safety risk at plant,” it said.

In Brussels, European Council President Charles Michel said the destruction of the civilian dam meets the threshold of a war crime and that his 27-member bloc “will hold Russia and its proxies accountable.”

NATO Secretary-General Jens Stoltenberg said destruction of the dam put thousands of lives at risk and will cause severe environmental damage.

“This is an outrageous act, which demonstrates once again the brutality of Russia’s war in Ukraine,” he tweeted.

In October, Zelensky warned that Russia was concocting reasons to commit a large-scale disaster, stating he had information that Kremlin forces had “mined the dam and aggregates of the Kakhovka hydroelectric power plant.”

He said that if the dam was blown, more than 80 settlements, including Kherson would be put at risk of flooding and hundreds of thousands of people may be affected.

In a second statement on Tuesday, Zelensky rejected the idea that Ukraine was behind the dam’s destruction, pointing to it having been occupied by Russian forces for more than a year.

“It was mined by the Russian occupiers. And they blew it up,” he said. “Russia has detonated a bomb of mass environmental destruction.”

In Washington, National Security Council spokesman John Kirby told reporters that there are casualties from the dam explosion and subsequent flooding but it was too early to known exact figures.

He said the White House is closely watching the situation and was working with Ukrainian counterparts to gather more information.

“What is clear and what we absolutely can say is that the damage to the Ukrainian people and to the region will be significant,” he said.