A South African military helicopter crashed during an anti-rhino poaching patrol over Kruger National Park, killing five people, the army said Sunday. "The helicopter was on a scheduled aerial patrol of the Kruger National Park as part of Operation RHINO, the anti-rhino poaching operation," Brigadier General Xolani Mabanga said in a statement. "A preliminary investigation is currently under way to establish the sequence of events that led to the fatal crash of the helicopter," he said, adding that the accident occurred on Saturday. The craft was an Agusta 109 deployed to Kruger, a huge game reserve in the north of the country, by the military, which has been assisting rangers in the fight against rhino poaching. Poaching figures have reached alarming levels. Only 13 rhinos were killed in 2007 but 188 have already been slain since the start of 2013, 70 percent of them in Kruger, according to environment ministry figures released on March 28. Amid the crisis, the South African government is mulling the legalisation of rhino horn trade in a bid to curb the slaughter. South Africa has had a moratorium on rhino horn sales since 2009. Rhino poaching is driven by a booming demand for their horns in the Asian black market where the fingernail-like substance is falsely believed to have powerful healing properties.