President Dilma Rousseff, who cut short a visit to Chile, has been visiting survivors at the city's Caridade hospital along with government ministers.

BBC: Brazil nightclub fire: Four arrested in Santa Maria

Dr Paulo Afonso Beltrame, a professor at the medical school of the Federal University of Santa Maria, went to the city's Caridade Hospital to help victims and said the "large amounts of toxic smoke" caused "at least 90%" of the deaths.

BBC: Eyewitness: Kiss night club fire in Santa Maria, Brazil