(CNN) - One person has been confirmed dead after a huge fire engulfed and destroyed a building Tuesday in the Brazilian city of Sao Paulo, according to state-run news agency Agencia Brasil.
The dramatic fire broke out on the fifth floor of the 26-story building, which collapsed in a fireball an hour and a half later, according to the Brazilian Civil Defense.
Seven other buildings were evacuated in the surrounding area. The blaze started at 1:36 a.m. Tuesday, according to a Sao Paulo Fire Department spokesman.
The building was owned by the federal government and had previously been the headquarters of the Federal Police. At the time of the fire it was abandoned from commercial use but occupied by low-income families who were part of the Front for Fighting for Housing, a social organization that advocates for fair housing, Agencia Brasil reported.
City authorities had been negotiating with the group to vacate the building since February, Sao Paulo City Hall said. In March, City Hall had registered 400 people living in the building.
There is no official information on the number of missing persons or on the identity of the one confirmed victim.
First responders were using dogs and removing rubble by hand in the hope of finding survivors, the Sao Paulo Fire Department tweeted. However, rescue efforts were delayed to allow the smoldering debris to cool.
As many as 160 firefighters in 57 vehicles responded to the massive fire at the building on the Largo do Paissandu in the center of the city.
Chef Nadja dos Santos Freitas filmed a video of the fire from the balcony of her apartment on nearby Avenida Ipiranga.
"The fire started at around 30 past midnight. My husband and I woke up with the noise of glass breaking," she said: "Every day we pass by there and we knew that there would be a tragedy. The building was in ruins; the fire department inspected it a short time ago."
An investigation is underway to determine the cause of the fire.
Lt. Guilherme Derriti, a spokesman for the Sao Paulo Fire Department, said haphazard living conditions may have contributed to the blaze.
"We have found various cooking gas cylinders, the electrical system was very precarious. They had used wooden panels to divide the resident areas, and a lot of rubbish that was thrown in the lift shaft, all this very inflammable elements may have contributed to the fast propagation of the flames."
The city government estimates that 70 other buildings, housing 4,000 families, are occupied in similar conditions in the city center. Sao Paulo Mayor Bruno Covas said during a press conference at the site of the fire that civil defense agents will inspect the buildings in the next 45 days, Agencia Brasil reported.
Correction: A previous version of this story said the building destroyed in the fire was an apartment building. The structure was a commercial building but had been occupied by low-income families who were a part of a group that advocates for fair housing.
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