A videograb shows the huge rock falling on boaters in Minas Gerais state, Brazil.

The death toll from an accident in which a slab of cliff rock toppled onto pleasure boaters on a Brazilian lake has risen to 10, police said on Sunday.

Authorities worked to identify the dead and divers were searching the lake in case there were more victims.

Police Chief Marcos Pimenta said there was a possibility that some people were missing following the accident Saturday in Minas Gerais state. At least 32 people were injured, though most were released from hospitals by Saturday evening.

Videos posted on social media showed tourists shouting as the column of rock smashed into the water. At least one wrecked boat sank, others sped away.

Firemen, including divers, said they were searching for 20 people believed to be missing.

The people hurt in the accident had broken bones and one was in serious condition in hospital with head and facial injuries. Some 23 others were treated for light injuries, fire department spokesman Pedro Aihara told reporters.