AT least 20 revellers have been injured – two seriously – at the Rio Carnival after an out-of-control float crushed them against a barrier.

One onlooker described the “horrible” moment the vehicle slammed into crowds on the first night of the elite samba school championship yesterday.

An accident at the Rio Carnival has left at least 20 injured

Monica Ferreira told Brazilian newspaper : “It was horrible. One of the ladies trapped on the railing was unconscious, lost a lot of blood.

“People were desperate, not knowing what to do.”

The horror unfolded after the Paraiso do Tuiuti samba school’s cars lost control at the beginning of the parade and jammed people against the railings separating the track from the bleachers.

Some of the injured were trapped by the vehicle as firefighters fought to rescue them.

One eyewitness described scenes of “mayhem”.

He said: “I nearly got hit by the car too as it totally lost control and went careering into the side of the barriers.”

Some 20 people were injured in the horror smash at the crowded street festival.

Eight of them, including journalists covering Rio’s biggest party, were hospitalised, while a further three remained in serious condition today.

Cops launched a probe as soon as the float finished its transit through the Sambadrome.

Police investigator William Lourenco Bezerra said the three drivers of the float would be questioned Monday morning, adding that one already had been identified as the main focus of enquiries.

Bezerra said: “The last float went into reverse and ended up pressing revellers against the fence on one side. That caused chaos.

“Then the drivers made a quick maneuver to the opposite direction and injured more people.

“The main driver of the float mixed with the rest of the samba school and left. But he has already been identified and will be investigated.”

The pavement of the Sambadrome was wet because of a persistent drizzle making the big floats harder to guide.

In a statement, samba school Paraiso do Tuiuti said: “Our board offers its deepest sentiments and is open to make any clarifications as soon as all the causes of the accident are investigated.

“We will offer all the assistance to the victims of this irreparable incident.”

Despite the accident, the head of the Rio parade, Elmo dos Santos, said that “the show must go on”.

Dos Santos told journalists: “The rain made the car veer to the left. Organizers tried to adjust, but then they lost control. It is all regrettable, but we cannot stop.”

Elmano Santos, a reveller from Rio, said the float missed him by inches.

He told reporters: “It was very quick. I saw a few journalists taking pictures close to the float get injured.”

Paraiso do Tuiuti was the first of six samba schools parading in the night’s extravaganza at the Sambadrome, which went on until early Monday.

Only partygoers at the entrance of the Sambadrome were aware of the incident. Many who found out later agreed with the decision to carry on.

Jonas Elias, a tourist from Salvador, said: “It is all very sad, but to stop Carnival would create an even bigger problem.

“Of course this spoils the party a bit, but to frustrate all this crowd would make the tragedy even bigger.”