Up to 100 people in the Russian-controlled town of Nova Kakhovka are trapped and thousands of wild animals have been killed after the Kakhovka dam in southern Ukraine collapsed, the town's Russian-installed mayor said, Russian news agencies reported.
Over 30,000 cubic metres of water was pouring out of the reservoir the dam held back every second and the town was at risk of contamination from the floods, the TASS news agency quoted the official, Vladimir Leontyev, as saying.
He said rescue efforts were being undertaken to free people trapped by the floods.
The RIA news agency reported him as saying that "thousands of animals" at the Nizhnedniprovsky National Nature Park had also been killed, and that the scale of the disaster was "huge".
Ukraine and Russia blame each other for the destruction of the dam, which has sent floodwaters across a war zone and forced thousands to flee. Some independent experts say the dam may have collapsed due to earlier damage and intense pressure on it.