Images posted on social media show the moment lightning struck near a demonstration by supporters of Brazil's former president Jair Bolsonaro, injuring 89 people, according to the fire department.
Thousands gathered on Sunday in the rain in Brasilia to support Bolsonaro, who was sentenced to 27 years in prison last year for leading a failed coup d'etat following his narrow re-election loss.
Footage shared online shows crowds with colourful umbrellas and plastic ponchos stunned by a sudden flash of light and rumbling sound.
Ambulances and firefighter vehicles rushed to the scene after several people were hit by lightning.
