A charter plane crashed at an airport near Pretoria, injuring about 20 people, according to emergency services.
ER24 spokesman Russel Meiring said that ER24 paramedics‚ along with several other services‚ were on the scene treating the injured.
"Seen on Sunday morning at Pretoria's Wonderboom Airport‚ ex Rovos Air Convair 340 ZS-BRV‚" the caption read.
"There is smoke all over and paramedics are on the scene", eNCA news quoted a local police spokesman as saying.
Mr Meiring said ER24 helicopters were on the scene to airlift any critical patients to hospital.
The plane was a Dutch cargo MAC Martin's Air Charter owned by Air France-KLM.
Everything we know about the Thailand cave rescue
Rescuing them all could take three to four days and depended on the weather, an army commander involved in the mission said. The acting Chiang Rai governor had said rescuers couldn't wait for ideal weather conditions because of several factors.
Aviodrome wrote on Facebook that it was "hugely shocked", by the crash.
The plane, which had been expected at the Aviodrome, "crashed in South Africa during take-off on a test flight", it said.
"We found 19 people inside the plane and we [also] had one deceased patient". It had just been refurbished for 350,000 euros ($410,000) at Wonderboom.
"We are not sure what happened at this stage", Rosella Passier, the Aviodrome's marketing manager, told AFP in The Hague.
Civil Aviation Authority investigators were at the scene and started the process of determining the cause of the accident.