At least eight people in Bolivia have died when a gas canister used by a street vendor exploded during the city of Oruro's famous carnival celebrations.

More than 40 others were injured, the authorities said.

Several victims had to be airlifted to Bolivia's main city, La Paz, as local hospitals struggled to cope.

Hundreds of thousands of people take part every year in Oruro's carnival celebrations.

The blast happened on Saturday evening on a crowded side street close to the main parade route.

At least three children died. Others were injured.

President Evo Morales wrote on Twitter that he was "dismayed at the news of the deaths caused by the explosion".

Local media reported that the explosion was accidental.

The Oruro carnival dates back more than two centuries and has been classified as a cultural heritage event by the United Nations.

Some 6,000 dancers - among an estimated crowd of some 450,000 - take part in the festivities every year.