Four children were among at least seven people killed after a bus overturned in Russia, officials said.

The bus had been carrying children from the western city of Smolensk to the Kaluga region, south of Moscow.

It came off the road and overturned, with pictures showing the bus entirely on its roof in the snow.

"As a result of a road accident, seven people were killed, four of whom were minors. 24 people were taken to hospital," the Kaluga region interior ministry said in a statement.

Most of the people taken to hospital were children, officials told Russian news agencies.


Footage released by local police showed firefighters carrying injured people on stretchers from inside the upside down bus.

Image: The driver is under criminal investigation after the crash

Its windows were smashed and the bumper was hanging off.

A criminal case has been opened against the bus driver, the Kaluga interior ministry said.

Russia is one of the worst countries in the world for road deaths, mainly due to alcohol, poor road conditions and failure to follow traffic regulations.

Fewer people have died in recent years but about 20,000 still die annually - 18.9 deaths per 100,000 people.

That is compared to the US which, with more than double Russia's population, had a road death rate of 10.0 per 100,000 people in 2013, according to the latest year data is available.