At least 6 people have been killed and 50 more injured after a stage collapsed at an election campaign rally in Mexico's northern Nuevo León state, the local governor has said.

The incident occurred as centre-left presidential candidate Jorge Alvarez Maynez was delivering a speech in the city of San Pedro Garza Garcia, near Monterrey.

Mr Maynez was uninjured in the collapse, and was seen speaking to supporters following the incident. Several members of his team had been hurt, he said.