JOHANNESBURG (AP) — A South African wildlife ranger was accidentally killed by a colleague who opened fire after they were charged by a buffalo during an anti-poaching patrol in Kruger National Park, the country's parks service said Friday.

Rangers attempted to shoot the buffalo after finding cover in the confusion of the charge on Thursday but the ranger sustained a fatal bullet wound to his upper body, the parks service said in a statement, citing the ranger who opened fire. A helicopter transferred the injured ranger to a clinic in Nelspruit city, but he died while being treated.

Reynold Thakhuli, spokesman for the parks service, described the shooting as a case of "friendly fire." He said the ranger who shot his colleague was receiving psychological counseling and police were investigating.

In a separate incident, rangers on Wednesday killed two suspected poachers in Kruger National Park after tourists on foot spotted a man with what appeared to be a hunting rifle and informed authorities, the parks service said. The suspects were killed after ignoring an order to surrender and opening fire on rangers, it said.

Kruger National Park has been heavily targeted by poachers who have killed rhinos in record numbers in recent years. An increase in elephant poaching was also reported in the park last year.