"Initial reports show that approximately 20 people had sustained injuries ranging from minor to critical".
"There is smoke all over and paramedics are on the scene", eNCA news quoted a local police spokesman as saying.
A plane crashed in Pretoria, South Africa, on Tuesday afternoon.
"At this stage, we can confirm that crew members are attending to the scene of a crash", he said.
"We can, at this point, confirm that there was one fatality".
Images from the site showed the plane broken into several pieces.
ER24 will move the treated patients to nearby hospitals, he said.
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The aircraft, a Convair 340 (ZS-BRV) was taking off from Wonderboom airport.
Paramedic Xander Loubser from BestCare Ambulance Service said: "There are critical patients".
The plane, which had been expected at the Aviodrome, "crashed in South Africa during take-off on a test flight", it said.
Russel Meiring of ER24 said at least 20 people were hurt.
The plane had the words "Martin's Air Charter" painted on it, which was a previous name of Dutch cargo airline Martinair.
The Aviodrome is one of the Netherlands' largest theme parks, where visitors can view various aircraft close up, including a KLM Boeing 747 and Soviet-era MiG-21 fighter jet.
"A statement with further details will be issued tomorrow", said Kabelo Ledwaba, spokesperson of the South African Civil Aviation Authority.