At least 73 people, including seven children, have died in a fire in a multi-storey building in the centre of Johannesburg, South Africa’s biggest city, TheGuardian.com reports.

In one of the country’s worst such tragedies in living memory, emergency management services said a further 43 people had been injured in the blaze, which broke out early on Thursday.

People had been evacuated from the building, and an emergency services spokesperson said a search and recovery operation was under way. It was likely the death toll would rise, Robert Mulaudzi said, and it was not immediately clear what caused the blaze. As of midday on Thursday, authorities had yet to count the casualties on the top two floors of the five-storey building.

“Over 20 years in the service, I’ve never come across something like this,” Mulaudzi said.

There was an “informal settlement” inside the building, Mulaudzi said. “So there [are] a lot of informal structures inside the building. There is a lot of debris that we have to remove.”

Omar Arafat, a resident of the building, said he was woken up at about 1am by loud bangs and screams of “fire, fire”. He rushed for the building’s front door, but his path was blocked by flames. With no other avenue of escape, he broke a window in his third-storey room and jumped.

He added that he did not remember anything else. “I was out for three hours,” the Malawian national said. When he regained consciousness, he was surrounded by fire engines and ambulances. There were dozens of bodies on the road around him. “When I got up, I thought: where is my sister?”

Joyce Adam, Arafat’s sister who also lived in the building, has yet to be accounted for. Her two-year-old daughter was thrown out of a window and caught by people on the ground. The child is being cared for by other family members.

At the scene on Thursday, hundreds of people gathered behind police lines hoping for word on friends and family members who lived in the building. “We have not been told anything,” said Mpathu Motani, who was waiting for news of her sister. “We are feeling very bad.”

The residents of the building were mostly from Malawi, Tanzania and Zimbabwe.