UPDATE: 5:20 a.m. EDT — The fire which started in a building in Largo do Paysandú, São Paulo, at 1:36 a.m. local time (12.36 a.m. EDT) Tuesday, was brought under control, according to a Sao Paulo Fire Department spokesperson.

As many as 160 firefighters in 57 vehicles worked to extinguish the massive fire. Although a tweet on the fire department’s official Twitter page said that a victim was trapped inside the burning building and was seen calling out for help from the top floor, no casualties or injuries have been reported yet.

Also, due to the partial collapse of the building, it was difficult for the fire department to estimate how many floors the building had.

The cause of the fire remains unknown.

Original story:

A building in Largo do Paysandú, the Republic region, in the center of São Paulo, Brazil, caught fire in the early hours of Tuesday. The building, which was abandoned and was being used by homeless people for shelter, collapsed even as firefighters were trying to bring the flames under control.

At least 24 units and 57 firefighter agents were battling the fire when the building collapsed, social media users who witnessed the incident said. As the building collapsed, it ended up burning the building next to it, which was ordered evacuated.

The collapse of the building, which appeared to be several floors tall, was caught on camera by a number of witnesses and news reporters who were at the scene.

According to Radio BandNews FM, the building was a discarded property of the federal police, and was occupied by a number of homeless people. An unspecified number of people were speculated to be still inside the building when it went up in flames and collapsed.

Although the firemen had not confirmed the cause of the fire, preliminary reports suggested it might have started on the fourth floor, following a gas leak and an explosion.

It was also not clear how many people were rescued from the building and how many remained trapped under the rubble.

This is a developing story.