The aircraft, a Bell 412 with registration number 5NBQG, departed Port Harcourt Military Base and was en route to an oil facility in Bonny Finnima when it crashed into the Atlantic Ocean.
Rescue efforts are underway, with three bodies recovered from the crash site and five others still missing.
The Nigeria Safety Investigations Board (NSIB) and the Nigeria Civil Aviation Authority have launched investigations into the cause of the accident. (ILKHA)