At least seven people are missing following the collapse of the Nova Kakhovka dam on Tuesday, the occupied town's Moscow-appointed mayor told Russian state-run news agency RIA Novosti.

"We are clarifying the information on the missing people now," Vladimir Leontiev said Wednesday, according to RIA.

"We know about seven people for sure."Earlier on Wednesday, Leontiev said 900 people had been evacuated so far and the water levels in Nova Kakhovka were decreasing after the dam's collapse caused extensive flooding.