SANTA MARIA, Brazil (Reuters) - Cities across Brazil are cracking down on nightclubs to ensure that they comply with fire regulations after a weekend blaze destroyed a club in the southern university town of Santa Maria, killing 235 people. The fire was Brazil's deadliest in half a century and the tragedy resonated across the country, with many people demanding those responsible be prosecuted and that the government tighten up on safety. Police said a flare that ignited the fire and was used by the band for visual effects was meant for outdoor use, the club's emergency exit signs were not working and the only available exit was too small. Outraged Brazilians blame what they see as lax regulation and corrupt officials for the tragedy. There are fears that similar fires could break out at other clubs and public venues, especially as the country gears up to host the soccer World Cup next year and the Olympic Games in 2016. Sensitivity is also growing in the run-up to next month's Carnival celebrations, which feature throngs of unruly revelers in parades and street parties in cities across the country. As funerals and an official investigation proceeded, government officials and lawmakers pressed for tougher laws. President Dilma Rousseff, who visited Santa Maria over the weekend, urged local officials on Monday for more rigor in enforcing safety regulations. "We were all evidently shocked by the Santa Maria tragedy," Bosco Saraiva, the acting mayor of Manaus, a city of 2 million people in the Amazon region, told Reuters. The campaign featured club inspections and city authorities closed 17 because of fire hazards and expired permits. Americana, a city in the southeastern state of Sao Paulo, issued a blanket order for all nightclubs to shut down temporarily while new safety standards are discussed. Brasilia and other cities including Sao Paulo and Rio de Janeiro have also deployed inspectors. In Salvador, Brazil's third-biggest city, the mayor ordered inspections of all entertainment venues, including Carnival installations now being erected. Safety experts have criticized carnival floats and decorations in the past because they are often made with paper, plastics and other highly flammable materials. Marchers carried flowers to a local gym that has served as a morgue and funeral parlor since the fire early on Sunday. The death of a 21-year-old man at a hospital in nearby Porto Alegre raised the death toll to 235, authorities said on Tuesday. An additional 121 people were still hospitalized, 83 of whom were in critical condition. Most of the dead were students suffocated by toxic fumes that rapidly filled the club after the flare set fire to soundproofing material on the ceiling. Witnesses said club bouncers initially blocked the exit because they thought fleeing customers were trying to leave without paying for their drinks. Families of the victims demanded explanations. "Somebody has to be responsible," said Elaine Marques Gonçalves, who lost one son in the fire and has another critically injured. "I will not get my son's life back, but I want the authorities to investigate and act, for the sake of other young people," she said in a video interview on the website of the O Estado de S.Paulo newspaper. Police have detained the two owners of the club and two members of the band whose performance led to the blaze. No charges have been filed against them, and prosecutors said they could be held for up to five days for questioning. The popular club was authorized to hold 690 people and was believed to have been packed with about 1,000 revelers at the time of the fire, police said. Santa Maria's police chief, Marcelo Arigony, said the band had bought a $1.25 outdoor flare at a local shop instead of spending $35 on a flare for indoor use. He said the club's fire extinguisher tags were either expired or falsified. "Any child could tell the place wasn't safe," Arigony told a news conference. The Kiss nightclub appeared to have no fire escape, no alarm and no sprinklers. Experts said the soundproofing material that caught fire was banned. Inspection in this country is a joke. It's time for that to change," said the owner of several nightclubs in Sao Paulo, who asked not to be named because of the sensitivity of his position. Additional reporting by Maria Carolina Marcello and Peter Murphy in Brasilia, and Eduardo Simões and Asher Levine in Sao Paulo; Writing by Anthony Boadle; Editing by Kieran Murray, Christopher Wilson and Mohammad Zargham