Floodwaters in southern Russia on Sunday threatened to submerge thousands more homes in the Kurgan region, where the governor predicted a "very difficult situation" in the coming hours.

There is widespread flooding in the Russian Urals regions and neighboring Kazakhstan, caused by melting ice swelling rivers, exacerbated by heavy rainfall.

In Kazakhstan, more than 107,000 people have been evacuated from their homes, while in Russia almost 40,000 homes have been flooded, TASS state news agency reported.

Spring flooding is a regular occurrence but this year it is much more severe than usual.

Kazakh President Kassym-Jomart Tokayev said earlier this month that this was the country's worst natural disaster for the last 80 years.

The floods have already submerged 34,000 homes in Russia's southern Orenburg region, due to the rising Ural River.

AFP journalists on Saturday saw residents being evacuated in boats and police vehicles in the regional capital Orenburg.

The situation is now worsening in the Kurgan region further east.

There, the level of the River Tobol was rising fast and Governor Vadim Shumkov said "A very complex situation with rising water is forecast for tonight".

Fresh rainfall was making the situation worse, Shumkov said, and the Tobol had just risen 25 cm (10 inches) in two hours. But some were refusing to evacuate, he complained.

The Russian emergency services ministry has predicted that more than 18,000 people could get flooded out in the Kurgan region, state news agency RIA Novosti reported.

In a post on Telegram, Shumkov urged residents to "leave the flooded areas immediately" while it was still daylight, warning that by nightfall, street lights might have to be switched off for safety reasons.