Around 20 people died and thousands were evacuated in Kazakhstan on Friday after severe floods destroyed two dams in the south of the Central Asian state, the emergencies ministry said.

Separately, a helicopter crashed in stormy weather during a parallel rescue operation in eastern Kazakhstan, killing all eight people on board, the ministry said.

The Kazakh emergencies ministry said two dams north of the financial capital Almaty had burst when melt water swept through the hilly area, flooding villages and causing mudslides.

About 20 bodies have been retrieved, Nurlan Serperbayev, a regional emergencies ministry official, told Reuters by telephone from the scene. The rescue operation is continuing.

Spring flooding is a frequent occurrence in Central Asia but a sudden rise in temperatures following weeks of heavy snow storms has exacerbated the problem this year.

The emergencies ministry said the latest floods mainly affected two settlements, Zhylbulak and Kyzyl-Agash, where a total of about 4,000 people were evacuated to safer areas.

President Nursultan Nazarbayev sent a message of condolences to the families of the victims, his office said in a statement.

A powerful gush of water had also washed away a bridge on a highway connecting Almaty with the eastern city of Oskemen.

In eastern Kazakhstan, where heavy snow storms severed entire districts from the rest of the country, a medical evacuation helicopter with eight people on board crashed in bad weather as it took part in the rescue operation.

Everyone died, said Anastasia Sklyar, a regional emergencies ministry spokeswoman.

Several key roads bisecting central Kazakhstan were closed for transport on Friday after snow storms swept through the area, trapping dozens of cars, local media reported.

Snow storms have been heavier than usual in Central Asia this year, cutting off remote villages in central and eastern Kazakhstan from regional centers and disrupting transport.