JOHANNESBURG (AP) — A hyena has mauled a 15-year-old boy at a camp in South Africa's Kruger National Park, sinking its teeth into the youth's face as he slept in a tent.

The grandfather of Erco Janse van Rensburg said Tuesday that the South African boy is in the intensive care unit of a Johannesburg hospital, where he has undergone reconstructive surgery.

Basie Smalberger says his grandson, who was airlifted to the hospital after the attack early Sunday, is severely sedated and that there is "slow progress" in his recovery.

South Africa's national parks service has expressed regret for the incident and says rangers went to the camp and searched in vain for the hyena. It says they found a hole under the fence around the camp where the hyena may have entered.