Eleven people were injured in Brazil early Tuesday during the fourth round of samba parades when a float collapsed under the weight of dancers - the second such incident in two days.
The incident, which took place around 3:00 am (0600 GMT) at the Unidos da Tijuca parade in Rio de Janeiro's Sambodromo, took place a day after a truck carrying a float ran into bystanders late Sunday, injuring 20.
Municipal health authorities said two of the 11 were seriously hurt.
There were chaotic scenes in the wake of the collapse, with ambulances arriving to evacuate the wounded and police shooing away dozens of photographers.
"I was on the platform of the float, on the left side, and all of a sudden I saw the right side collapse," weeping dancer Raissa Ribeiro told AFP.
Sunday's accident took place on the first night of the elite samba school championship when the colorful float at the tail end of the Paraiso do Tuiuti parade swerved on the crowded runway, crushing people against a fence.
Eight of them, including journalists covering Rio's biggest party, were taken to hospital, and three remained in serious condition Monday.
The samba parades and street parties known as "blocos," in which hundreds of thousands of people drink and dance, often in skimpy outfits, provide a huge boost to Rio's economy.
They attract more than a million tourists and almost $1 billion in revenues, according to officials.
Brazilians living through two years of steep recession and nearly 13 percent unemployment have grasped this year's carnival as a chance to let off steam.