Officials estimated between eight and 10 people could be trapped under the rubble, O Globo reported.
Fire Department Captain Mark Palumbo called the work of trying to locate and extract people trapped in the rubble "time consuming" that required "a lot of technique and a lot of patience."
At least 19 people were sent to the hospitals with injuries ranging from slight to severe, officials said.
Fire officials said debris from the collapsed commercial building destroyed nearby houses.
Fire Department Captain Mark Palumbo said the building had been under construction for about three months.