The floods sparked evacuations of thousands in the Orenburg region, 1200km, southeast of the capital, Moscow, after a dam on the Ural River burst last week under the pressure of surging waters.

Water levels in the river have since been fluctuating in different parts of the region, affecting the number of flooded houses.

Experts have cited multiple possible causes of the floods: large snow reserves in the area melting, deep freezing of the soil which does not allow it to absorb rain or melting snow, and a massive release of water from the Iriklinksy reservoir in the eastern part of the region into the Ural River.

Authorities have classified the deluge as an emergency of federal importance, and more than 16,500 people have been forces to leave the flooded areas, the office of the Orenburg governor said on Tuesday.

In the city of Orenburg, the region's capital, about 5500 houses remain flooded even as water levels in the Ural River in the city gradually decrease, according to officials.

The situation is more dire in the southwest of the region near the Kazakh border, where authorities said the river has risen to a dangerous level in the town of Ilek.

Further east along the border, floods also hit the regions of Kurgan and Tyumen after as water levels rose in local rivers. Russian emergency officials said more than 300 homes had been flooded in the Kurgan region.

In both the Kurgan and Tyumen provinces, evacuations from areas that might be flooded are under way.

In neighbouring Kazakhstan, massive floods have prompted the evacuation of more than 113,000 people to date, Kazakh emergency officials said.

As of Tuesday, more than 5700 houses remained flooded there, officials said.

Australian Associated Press