Assailants in South Africa attacked one of the country’s top triathletes as he was cycling to a training session and cut into his legs with a blunt saw, causing severe injuries.

Mhlengi Gwala, 27, was undergoing surgery after the attack which occurred before dawn on Tuesday in Durban, said Dennis Jackson, director of the elite athlete program for KwaZulu-Natal province.

Several attackers pulled Gwala off his bike as he cycled up a steep hill and sawed into his right calf, damaging muscle, nerves and bone, according to Jackson, who spoke by phone to the triathlete about the ordeal. The attackers missed a main artery and surgeons are confident they can save the leg, Jackson said. The attackers also started sawing into Gwala’s left leg before fleeing, enabling the athlete to crawl to a road and flag down a passing car to take him to a hospital.

The grisly attack has alarmed athletes in Durban who train early in the morning, when few people are on the roads. There was no immediate explanation for why Gwala was targeted and Jackson said the athlete had been attacked despite offering his cell phone, wallet and bicycle to the assailants. “I have never heard of any enemies that he may have,” Jackson said. “He is a wonderful ambassador for the sport.”

A friend of mine, cycling in the Durban area was robbed by three people this morning, Then they attempted to saw off both legs with a chainsaw. Blade too blunt and only got half way through one and started on the other. Absolutely disgusting! How safe are we on SA roads? — Henri Schoeman (@H_Schoeman) March 6, 2018

Gwala overcame drug and alcohol addictions and went on to represent South Africa at international competitions in Chicago in 2015 and in the Netherlands last year, Jackson said.

South Africa’s deputy sports minister, Gert Oosthuizen, described the attack on the “star athlete” as “totally unacceptable” and said police are investigating.

Triathlete Henri Schoeman, who won bronze for South Africa at the Rio Olympics in 2016, said he wishes Gwala the best on his path to recovery. “How safe are we on SA roads?” Schoeman said on Twitter.