Thousands of people are being evacuated in the Russian Urals after a section of the embankment dam burst in the mountain city of Orsk, officials say.
Heavy earth-moving machinery is on site trying to shore up the dam.
Earlier, an emergency was declared across the entire Orenburg region after levels in the Ural River rose dangerously because of melting ice.
Officials say 10,000 residents may be in the flooding zone and up to 4,000 houses could be inundated.
"Work in the area of the dam rupture in Orsk continues," the Russian Emergencies Ministry said in a statement, adding that around 440 people and 217 pieces of equipment were involved in the effort.
Russian state media said residents of two of the three districts of Orsk were being evacuated.
"Citizens of the Leninsky and Sovetsky districts of Orsk are being evacuated to temporary accommodation centres," the regional prosecutor's office said in a message.
Local emergency services said they were working to stem the flooding in Orsk, about 1,800km (1,100 miles) east of Moscow.
Orsk has a population of about 230,000. The evacuees are being moved to nearby schools.
Unverified footage on the Telegram messenger app appeared to show water gushing through a breach in an earthen dam.
The region - which includes Orsk, other Urals provinces and parts of neighbouring Kazakhstan - has been hit by widespread flooding in recent days.
