The crash happened Saturday evening in South Africa's Kruger National Park and that the crew was among those killed, the military said.
The helicopter was on a scheduled patrol of the park and an investigation has begun to determine the cause of the crash, the military statement said. It identified the aircraft as an Agusta A109 light utility helicopter.
South Africa is struggling to stem rampant poaching of rhinos, whose horns are sold to buyers in Asia.
The number of rhinos poached in South Africa since the beginning of the year has increased to 188, including 135 in the Kruger park alone, South African authorities said last week.
Also last week, South African media quoted authorities as saying three rhino poachers from neighboring Mozambique were shot and killed by game rangers in the Kruger park.
Rhino horn is made of keratin, a tough protein found in human fingernails. There's a belief in Asia that ingesting ground-up rhino horn cures diseases. However, no medical evidence supports that.
