The South African city's emergency services, on Thursday revealed that more than 60 people died in a fire that engulfed a five-storey building in central Johannesburg.

This was revealed by the spokesman of the Emergency Management Service, Robert Mulaudzi, who stressed that another 43 were injured, some suffering from smoke inhalation, were taken for treatment at local hospitals.

"We are now on 63 fatalities and 43 people injured who were transported to various healthcare facilities," said Mulaudzi.

Mulaudzi noted that firefighters at the scene put out the flames, stating that  search and recovery operations were ongoing."We are moving floor by floor conducting these body recoveries," Mulaudzi told local broadcaster ENCA.

"It is indeed a sad day for the city of Johannesburg. Over 20 years in the service, I've never come across something like this," Mulaudzi said.

It was not immediately clear what caused the blaze, which broke out overnight, as the building, which has been evacuated, is located in a deprived area of what used to be the business district of South Africa's economic hub, and was used as an informal settlement, Mulaudzi said.

"A lot of people" might have been trapped inside when the fire started, he added, suggesting many in the building may have been squatting illegally.

Fire trucks and ambulances were parked outside the red and white building with burned-out windows, which has been cordoned off by police, as a small crowd of onlookers gathered in the area.

In June a blaze ripped through a dilapidated building in Johannesburg and killed two children under ten who were locked in an apartment.