The destruction of a major dam in Ukraine will have “grave and far-reaching consequences for thousands of people”, the United Nations has warned.
UN aid chief Martin Griffiths said the scale of the catastrophe at the Kakhovka dam in southern Ukraine would only become clear in the coming days.
Thousands have fled flooded homes in the area, an active war zone. There are fears water levels could rise further.
Ukraine and Russia have accused each other of blowing up the dam on Tuesday.
The claims by the warring sides have not been verified by the BBC.
Addressing the UN Security Council late on Tuesday, Mr Griffiths warned that thousands of people in southern Ukraine were facing “the loss of homes, food, safe water and livelihoods”.
As mass evacuations continue on Wednesday morning in Ukraine’s Kherson region, satellite images have emerged showing widespread devastation there.
One of the photos showed a flooded port and industrial area in the regional capital Kherson, which is under Ukrainian control.
On Wednesday morning, 23 localities remained flooded, Ukrainian TV said in its latest news bulletin.
Overall, about 40,000 people needed to be evacuated, Ukraine’s Deputy Prosecutor-General Viktoriya Lytvynova said earlier: 17,000 in Ukraine-held territory west of the Dnipro River and 25,000 in the Russian-occupied east.
Some local residents have been seen desperately trying to save their belongings in homes with water levels nearing the ceiling.