(Reuters) - A fire in a nightclub killed at least 245 people in southern Brazil on Sunday when a band's pyrotechnics show set the building ablaze and fleeing patrons were unable to find the emergency exits in the ensuing panic, officials said.The blaze in the southern city of Santa Maria was started when a band member or someone from its production team ignited a flare, which then set fire to the ceiling, said Luiza Sousa, a civil police official. The fire spread "in seconds," she said.An estimated 500 people were in the Boate Kiss nightclub when the fire broke out early on Sunday, and many were unable to find the exits as dark smoke quickly filled the room. At least one exit was locked, trapping hundreds inside to die, many from asphyxiation as they inhaled smoke, police said."When I looked around, all I saw were dead bodies all around, lying on the floor. It was macabre," survivor Taynne Vendrusculo told GloboNews TV. "It all happened so fast. Both the panic and the fire spread rapidly, in seconds."Television footage showed people sobbing outside the club, while shirtless firefighters used sledge hammers and axes to knock down an exterior wall to open up an exit.By noon (1400 GMT), the death toll had risen to 245 and 48 people were being treated in local hospitals, said Major Cleberson Bastianello, head of the military police unit leading the rescue efforts. He said all of the bodies of the victims had been removed from the nightclub.President Dilma Rousseff, who started her political career in the same state where the fire happened, cut short a visit to Chile to return to Brazil to visit the scene. Before departing, Rousseff gave a televised statement in which she broke out in tears as she pledged government help for the victims and their families."We are trying to mobilize all possible resources to help in the rescue efforts," she said. "All I can say at the moment is that my feelings are of deep sorrow."The disaster recalls other incidents including a 2003 fire at a nightclub in West Warwick, Rhode Island, that killed 100, and a Buenos Aires nightclub blaze in 2004 that killed nearly 200. In both incidents, a band or members of the audience ignited fires that set the establishment ablaze.Brazil's safety standards and emergency response capabilities are under particular scrutiny as it prepares to host the 2014 World Cup soccer tournament and the 2016 Olympics.The Boate Kiss nightclub was a popular venue in Santa Maria, a university town of more than 275,000 people. The massive nightclub sometimes attracts up to 2,000 people on a given night, according to reviews on the Internet.One of the club's owners had already surrendered to police in Santa Maria for questioning, GloboNews reported.Rio Grande do Sul state Health Secretary Ciro Simoni said emergency medical supplies from all over the state were being sent to the scene.Santa Maria is some 186 miles west of the state capital of Porto Alegre. "A sad Sunday!" tweeted Rio Grande do Sul Governor Tarso Genro. He said "all possible measures" were being taken in response.(Additional reporting by Guillermo Parra-Bernal, Gustavo Bonato, Leila Coimbra, Todd Benson, Jeferson Ribeiro and Brian Winter; Editing by Todd Benson, Kieran Murray and Eric Beech)