One person has died and several more are feared dead or trapped
A rescue mission is under way to find survivors after a tower block in Brazil collapsed during a huge fire.
One person has been confirmed dead and several more are feared dead or trapped after screams for help were heard from the top floor of the building in Sao Paulo.
The tower block was occupied by rough sleepers and a number of people are thought to be trapped in the rubble, authorities said.
Firefighters were alerted at 1.30am local time (5.30am in Ireland).
More than 170 firefighters are at the scene, along with a civil defence response team and the army.
It is not clear how many people were in the building at the time but 50 families are registered as living in the block, according to local media.
Firefighter Andre Elias told Globo TV that they expected to find more victims but did not know how many.
Local workers said the former Federal Police building was 26 storeys tall and occupied by groups of homeless people.
Flabio Gabia, a receptionist at a nearby hotel, said: "When I went to see what it was, the streets were filled with desperate people.
"I heard several people shouting."
The blaze is understood to have started on the third floor and then spread rapidly to the levels above.
A neighbouring building was evacuated as the flames spread and the area has been sealed off by police.
Frederick Ludwig, a pastor at a nearby church, said he had been warning authorities for years about the appalling conditions for people living in inside the building.
He told the Folha de Sao Paulo newspaper: "There was sewage in the open air in there as well as outbreaks of dengue mosquito."
The cause of the fire is not yet known.