Ukraine has accused Russian forces of blowing up a vast dam in a Russian-controlled area on the front lines of the war, threatening hundreds of thousands of people across the region and potentially endangering Europe's largest nuclear power plant.
Water surged through the critical Kakhovka dam Tuesday, according to videos verified by NBC News and local officials, unleashing flooding across the war zone in southern Ukraine, sparking evacuations, and triggering warnings of an “ecological disaster.”
The dramatic incident could have far-reaching consequences on the battlefield and beyond. At least one town next to the dam was already completely flooded, according to its mayor, and officials are concerned about drinking water supplies throughout the region.
The dam breach comes after Kyiv’s forces appeared to launch a new series of attacks across the front lines in the south and the east, fueling speculation that their long-awaited counteroffensive may have begun.
The incident could raise international attention on the brutal costs of the war, more than 15 months after Russian President Vladimir Putin launched his invasion.
Both sides pointed fingers. Top officials in Kyiv accused Moscow of a "terrorist attack" and raised international alarm, while Russian officials blamed Ukraine and attempted to downplay the gravity of the situation.
NBC News has not verified the claims of either side about the dam, which sits in the front-line Kherson region.
The United States government has intelligence that is leaning towards Russia as the culprit of the attack on the dam in Ukraine, according to two U.S. officials and one Western official. President Joe Biden’s administration was working to declassify some of the intelligence and share it as early as Tuesday afternoon.
National Security Council spokesman John Kirby told reporters at the White House on Tuesday afternoon that the U.S. government "cannot say conclusively" who was behind the attack In a briefing, a spokesman for the State Department echoed those comments.
United Nations Secretary-General António Guterres told reporters in New York that the U.N. did not have independent information to verify why the collapse happened, but described it as "yet another example of the horrific price of war on people."
Throughout the war, Ukrainian and Russian officials have accused each other of targeting the dam with attacks, while Kyiv has voiced fears that Moscow would destroy it to trigger a devastating flood.
On Tuesday morning, Ukrainian officials warned that floodwaters would reach critical levels within hours and urged people on both sides of the Dnieper River to evacuate. Ukraine's state emergency service said about 1,300 people had been evacuated by 3 p.m. local time (8 a.m. ET.)
Around 80 settlements were in danger of flooding, Ukrainian President Volodymyr Zelenskyy said, ordering a mass evacuation from risk areas.
"Russia has detonated a bomb of mass environmental destruction," Zelenskyy said in a statement, calling it "the largest man-made environmental disaster in Europe in decades."
He blamed the Kremlin, describing Putin's regime as "the most dangerous terrorist in the world."
"It is physically impossible to blow it up somehow from the outside, by shelling," he said, responding to Russian claims that Ukraine had carried out the destruction. "It was mined by the Russian occupiers, and they blew it up."
Mykhailo Podolyak, one of Zelenskyy's advisers, argued that Putin’s forces had an "obvious" goal: "to create obstacles for the offensive actions of the armed forces."
Putin's government, for its part, called the breach an act of “sabotage” by Ukraine, with Kremlin spokesman Dmitry Peskov strongly denying allegations of Russian involvement.
Vladimir Saldo, the Russian-installed head of the Kherson region, said in a video posted on Telegram that "a missile attack" by Ukraine had hit the dam, but he insisted the situation was manageable and a major evacuation was not required.
"It will not prevent our military from defending the left bank," Saldo said, referring to the side of the river that Russia controls. However, he admitted that agricultural fields along the river bank had been washed away and civilian infrastructure disrupted.
Vladimir Leontiev, the Russian-installed mayor of Nova Kakhovka, a town that sits just across from the dam, said the area was completely flooded hours after the incident, according to the state news agency Tass.
Earlier in the day, Leontiev said the water level there had already reached more than 32 feet and about 300 houses located on the banks of the Dnieper were being evacuated.
Nuclear plant risks
Experts have speculated that destruction of the dam — which holds a volume of water equal to that of the Great Salt Lake in the United States — could devastate local communities and the environment.
The Soviet-era dam, 30 yards tall and 2 miles long, was built in 1956 on the river as part of the Kakhovka hydroelectric power plant.
Water from the reservoir helps cool the nearby Russian-controlled Zaporizhzhia nuclear plant and supplies drinking water to Crimea, the peninsula that was illegally annexed by Putin in 2014.
Ukraine’s state energy company, Energoatom, said that the dam breach could have “negative consequences” for the nuclear plant but that the situation was still under control.
The International Atomic Energy Agency said it was monitoring the situation and there was no immediate nuclear safety risk at the plant.
The overall damage likely to be caused by the breached dam “looks much worse” than a worst-case scientific model from last year because the water level of the reservoir was so high, a leading water expert said.
“It’s a massive disaster," said Henrik Ölander-Hjalmarsson, CEO and founding partner of Dämningsverket AB, a Swedish hydrological modeling company, who wrote a “catastrophic dam break scenario” at the request of UNICEF last year.
Tuesday's alarming developments came a day after Russia said that Ukraine’s military had launched a significant attack in a bid to break through its defenses on the war’s southeastern front lines.
Reports of heavy fighting from officials in Moscow and the country’s cadre of influential military bloggers fueled speculation that it could be the beginning of the major counteroffensive that Kyiv has been preparing for months.
Ukraine denied claims that a major offensive had been thwarted, accusing Russia of lying to sow distrust and suggesting that the long-anticipated attack was yet to come.
It was not immediately clear whether either side benefits from the damage to the dam, but it could hinder Ukraine’s military efforts in the south as it deluges swaths of land.
The Kremlin made the opposite case, accusing Ukraine of blowing up the dam because its purported offensive was failing. Tuesday’s “sabotage is also connected with the fact that having started large-scale offensive operations two days ago, the Ukrainian armed forces are not achieving their goals,” Peskov said.
The Kherson region was one of four annexed by the Kremlin last year, but it is only partly controlled by Moscow’s forces after a previous Ukrainian offensive recaptured the regional capital of the same name.