The situation is "critical", Salmin said, with water levels in the Ural River surging 40 centimetres over the past 10 hours to a height of 11.43 metres.

The deluge of melt water has forced over 120,000 people from their homes in Russia's Ural Mountains, Siberia and Kazakhstan as major rivers such as the Ural, which flows through Kazakhstan into the Caspian, overwhelmed embankments.

(Reporting by Reuters; Writing by Maxim Rodionov; Editing by Andrew Osborn)