Updated

A fire at a five-story building in downtown Johannesburg Thursday morning left at least 73 people dead and more than 50 injured, city officials announced.

The fire in South Africa's largest city broke out around 1:30 a.m. local time, according to the City of Johannesburg Emergency Management Services. When firefighters arrived at the scene, crews immediately began evacuating those inside the building and working to contain the fire.

As of 8 a.m. local time, the flames were mostly extinguished, but smoke was still trickling out of windows. 

Spokesman Robert Mulaudzi said a search and recovery operation was underway within the building and 73 bodies had been pulled out so far. The Associated Press reported seven children were among the dead, including a 1-year-old.

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Fire in downtown Johannesburg

At least 73 people are dead and 52 are injured after a multi-story building fire in Johannesburg, South Africa. (City of Joburg EMS/Facebook)

Johannesburg fire

Firefighters in Johannesburg, South Africa, work to recover bodies from a five-story building after an early morning fire ripped through in the city's downtown area. (REUTERS / Siphiwe Sibeko)

There were also 52 people treated for injuries, Mulaudzi said. The extent of their injuries was not revealed, but he said most were transported to hospitals in the area for further care.

Relief for families affected by the fire has been activated by City of Johannesburg Disaster Management.

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Charred building after fire in Johannesburg

The building where the fire broke out had been overtaken by homeless people, according to Joburg EMS spokesman Robert Mulaudzi, and could have had as many as 200 people living in it. (Michele Spatari / AFP)

Mulaudzi said the building had been overtaken by homeless people looking for a place to live without formal lease agreements, which made it difficult to search, according to The AP.

"This is a tragedy for Johannesburg. Over 20 years in the service, I’ve never come across something like this," Mulaudzi told the outlet.

City officials said 141 families – many believed to be foreign nationals – were affected by the tragedy, though the exact number of people inside the building when the fire broke out was unclear.

Witnesses told local news outlets there could have been as many as 200 people living in the building.

Johannesburg fire

The cause of the deadly fire in Johannesburg, South Africa, remains under investigation. (REUTERS / Siphiwe Sibeko)

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Though the cause of the fire remains under investigation, local government official Mgcini Tshwaku said there were indications that squatters and homeless people inside the building would light fires to keep warm during the winter, according to The AP.

This is a developing story. Check back for updates.