Thousands are being evacuated in a region of south-western Russia because of floods made worse by a dam burst in Orsk city, 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.

Officials said more than 1,100 residents of Orsk were being evacuated, as well as thousands more in the wider region.