Hundreds of thousands of people in Ukraine could lose access to drinking water after a major dam was attacked and effectively destroyed in a Russian-controlled region of southern Ukraine, President Volodymyr Zelenskyy said.

The sheer magnitude of the catastrophe is becoming clear as water continues to cascade through the breached wall of the collapsed Nova Kakhovka Dam. Floodwaters are still rising. The city of Kherson is less than 50 miles away from the dam, and homes near the dam have already been swept away. Ground that was once fertile is now a soggy wasteland, and thousands have been evacuated even as the war rages around them. 

According to Ukrainian officials, 80 communities are in the "flood zone" and more than 17,000 people were in the process of being evacuated, while over 40,000 people were in danger. 

"I know it's war, but to blow up the dam? It's barbaric," one woman told CBS News. 

One man was seen cursing Russia as he waded through murky water, carrying his 80-year-old mother's remaining possessions. 

Kherson has been on the front lines of the war for months. Earlier in the war, it was captured and occupied by Russian forces for eight months before being liberated in November. In February, "60 Minutes" reported that the city had been shelled over 2,000 times in the past three months, and Halyna Luhova, the woman charged with rebuilding the city and managing problems caused by the shelling, said that Russian forces had been targeting schools, humanitarian aid points and critical infrastructure. 

"During a long period of occupation for eight months, they know all the information as for our infrastructure," Luhova said in February. "So they know everything."

Russia accused Ukraine of blowing up the dam, a claim that Zelenskyy refuted. Russia was in control of the dam at the time of the attack, and Zelenskyy said it was impossible to destroy the facility from the outside. The Kremlin has continued to deny any involvement in the attack. 

The dam holds back a reservoir containing about the same volume of water as the Great Salt Lake in Utah. The dam is important for the safe operation of the Russian-controlled Zaporizhzhia nuclear plant, which has been under threat during the war and relies on water pumped constantly from the reservoir to cool radioactive fuel. 

The United Nations' atomic energy body says the plant remains safe for now. The head of the agency said Tuesday the reservoir contained enough water to serve the plant for "a few days," and said a backup source at the facility would be able to keep the plant operating for months as long as it remained intact. 

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• War
• Ukraine
• Russia