Updated 3:20 a.m. EST
SANTA MARIA, Brazil A fast-moving fire roared through a crowded, windowless nightclub in southern Brazil early Sunday, filling the air in seconds with flames and a thick, toxic smoke that killed more than 230 panicked party-goers, many of whom were caught in a stampede to escape.
Inspectors believe the blaze began when a band's small pyrotechnics show ignited foam sound insulating material on the ceiling, releasing a putrid haze that caused scores of university students to choke to death. Most victims died from smoke inhalation rather than burns in what appeared to be the world's deadliest nightclub fire in more than a decade.
The Federal University of Santa Maria confirmed to CBS News that 101 of its students were among the dead.
The first funerals for victims were set to begin Monday morning.
Survivors and a police inspector, Marcelo Arigony, said security guards briefly tried to block people from exiting the club. Brazilian bars routinely make patrons pay their entire tab at the end of the night before they are allowed to leave.
But Arigony said the guards didn't appear to block fleeing patrons for long. "It was chaotic and it doesn't seem to have been done in bad faith, because several security guards also died," he told The Associated Press.
Later, firefighters responding to the blaze initially had trouble getting inside the Kiss nightclub because of "a barrier of bodies blocking the entrance," Guido Pedroso Melo, commander of the city's fire department, told the O Globo newspaper.
Authorities said band members who were on the stage when the fire broke out later talked with police and confirmed they used pyrotechnics during their show.
Police inspector Sandro Meinerz, who coordinated the investigation at the nightclub, said one band member died after escaping because he returned inside the burning building to save his accordion. The other band members escaped alive because they were the first to notice the fire.
"It was terrible inside -- it was like one of those films of the Holocaust, bodies piled atop one another," said Meinerz. "We had to use trucks to remove them. It took about six hours to take the bodies away."
Television images from Santa Maria, a university city of about 260,000 people, showed black smoke billowing out of the Kiss nightclub as shirtless young men who attended the university party joined firefighters using axes and sledgehammers to pound at the hot-pink exterior walls, trying to reach those trapped inside.
Bodies of the dead and injured were strewn in the street and panicked screams filled the air as medics tried to help. There was little to be done; officials said most of those who died were suffocated by smoke within minutes.
Within hours, a community gym was a horror scene, with body after body lined up on the floor, partially covered with black plastic as family members identified kin.
Outside the gym, police held up personal objects -- a black purse, a blue high-heeled shoe -- as people seeking information on loved ones crowded around, hoping not to recognize anything being shown them.
Teenagers sprinted from the scene after the fire began, desperately seeking help. Others carried injured and burned friends away in their arms. Many of the victims were under 20 years old, including some minors. About half of those killed were men, about half women.