At least 52 people died when a fire ripped through a multi-story building in Johannesburg, South Africa’s biggest city, emergency services said Thursday.

Emergency Services spokesman Robert Mulaudzi said another 43 people were injured in the blaze that broke out in the predawn hours.

He said the death toll might still increase.

A search and recovery operation was underway and firefighters were moving through the building, Mulaudzi said.

The team had pulled 52 bodies out so far, he said, adding that more people might be trapped inside.

At least one child was among the dead, Mulaudzi said.

Authorities said the fire had been largely extinguished, but smoke still seeped out of windows of the blackened building downtown.

Strings of sheets and other materials also hung out of some of the windows.

It was not clear if people had used those to try and escape the fire or if they were trying to save their possessions.

Mulaudzi said the building was effectively an “informal settlement” where homeless people had moved in looking for accommodation without any formal lease agreements.

He said that made it hard to search the building.

There might have been as many as 200 people living in the building, witnesses said.