An eight-year-old girl was seriously injured in the tragedy and remained the only survivor of the mishap.

She was taken to hospital for treatment.

The accident occurred when the bus crashed through a barrier and caught fire when it hit the ground.

According to reports, passengers were travelling from Botswana's capital Gaborone to an Easter service in the town of Moria.

The vehicle lost control and went off a bridge on the Mmamatlakala mountain pass between Mokopane and Marken, around 300km (190 miles) north of Johannesburg, according to South African public broadcaster SABC as quoted by BBC.

Rescue operation was going on till late Thursday evening.

"I am sending my heartfelt condolences to the families affected by the tragic bus crash near Mamatlakala. We continue to urge responsible driving at all times with heightened alertness as more people are on our roads this Easter weekend," Minister of Transport Sindisiwe Chikunga was quoted as saying by Xinhua.

The cause of the cars is currently under investigation.