The top of a float collapsed during Rio de Janeiro's world famous Carnival parade early Tuesday, injuring at least 15 people, officials said.

The incident involved the second float of the popular samba school Unidos da Tijuca, themed around the Carnival in New Orleans. Revelers cried on the pavement and in the stands as injured people were removed by rescuers.

Police were investigating the cause of the accident.

Rio City Hall said in a statement that among the 15 injured at the city's Sambadrome, five were taken to the hospital and two were in serious condition.

The parade had to be stopped for almost 25 minutes so the injured could get medical attention. The show was allowed to proceed.

Reveler Felix Souza said he was dancing next to the float when the incident happened.

"We heard a burst on the top," he said. "People started screaming, we didn't understand what it was. It was a moment of despair for all there."

Unidos da Tijuca officials said their floats had been tested repeatedly before Carnival and regretted the incident.

On Sunday, a float of samba school Paraiso de Tuiuti crashed and injured at least 20 people, including three seriously. Following that accident, organizers also decided to proceed with the show.