Ukraine’s military said on Tuesday that Russian forces blew up a major dam in southern Ukraine, while Moscow-installed official in the city of Nova Kakhovka in the Russian-controlled parts of the Kherson region denied it.

“The Kakhovka (reservoir) was blown up by the Russian occupying forces,” the South command of Ukraine’s Armed Forces said on Tuesday on its Facebook page.

“The scale of the destruction, the speed and volumes of water, and the likely areas of inundation are being clarified.”

Reuters was unable to immediately verify the Ukrainian statement.

Earlier, Russian state news agency quoted the Moscow-installed mayor of Nova Kakhovka as denying the reports.

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“Everything is quiet and calm, there is nothing at all,” Russia’s TASS agency cited the mayor, Vladimir Leontiev as saying.

The dam has been damaged before in the 15-month-long Russia’s war in Ukraine.