Authorities told CNN they have moved through the building floor by floor, searching for survivors and pulling out charred bodies and laying them on the streets.

More than 50 other people were injured, Robert Mulaudzi, a spokesperson for the city’s emergency services, told CNN.

Wiseman Mpepa, who survived the fire, told CNN he woke up to people screaming. After seeing the fire blocking the building’s exit, he broke his window, but struggled to climb through.

Mpepa said he tried to tell other people in the building to go a gate to exit the building, but the gate was shut.

“They closed the gate,” he told CNN on the ground. “After that, I had no plan. I just sat (in my room).”

The cause of the fire, which has been extinguished, is still unknown.

Mulaudzi said the fire incident happened in a 'hijacked' building.

What are hijacked buildings?

In South Africa's  Johannesburg city, several hijacked buildings are present.

These buildings have been abandoned by their landlords and since then taken over by criminal gangs that lease them out illegally.

In the 1990s and 2000s, criminal syndicates began to "hijack" buildings that were left empty and rented them out illegally, reports ABC News.

According to reports, these buildings even became dilapidated centres of drug crime and other illegal activities.

In some cases, the syndicates occupied buildings with false title deeds, Angela Rivers, the general manager at Johannesburg Property Owners and Managers Association, told ABC News.