National Institute of Civil Aviation chief executive Joao de Abreu blamed adverse weather conditions and overweight as likely causes of the air crash.
"The accident occurred around 11:40 p.m. During the take-off, the aircraft failed to reach its cruising altitude and crashed over a dense forest,” De Abreu told journalists.
He said three of the occupants were in need of medical care and had to be evacuated to treatment in neighbouring South Africa.
The aircraft was traveling to Kruger Park in South Africa.
Abreu said technical teams have already gone to the field to determine the real causes of the accident.