The truck was at the tail end of the Paraiso do Tuiuti samba school parade in the city's Sambadrome when the accident occurred.
Fatal collision: Seven children killed as truck hits school van
It drove too close to a fence at the entrance to the competition piste, leaving several people unable to escape.
Three were seriously injured, including a news photographer. The truck was topped with one of the extravagant floats.
Of the 20 people injured in the accident "eight were sent to hospital in ambulances," including three severely injured women, the Health Secretary of Rio de Janeiro's office said.
But despite the incident, the party soon got back in swing.
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