[Read more: Rhino poacher killed by elephants then eaten by lions in South Africa.]

“There was nothing we could do before that,” Mr. Fox said. “It was getting dark — too unsafe to be on foot.” He added, “Once lions have taken down a human, you cannot be on the ground with them.”

To get to the remains, the rangers had to shoot the lions with darts to knock them out.

The men killed had been carrying a high-caliber rifle and an ax for chopping off the horns of the animals they planned to hunt, Mr. Fox said. They also had food to last several days — “mostly bread,” Mr. Fox said — and wire cutters for getting through fences. His estimate of three victims was based on counting their clothes and shoes.

Rhino horn is worth about $9,000 per pound in Asia, driving a lucrative and illicit trade. It is a prized ingredient in Chinese traditional medicine and is considered a status symbol.

South Africa is home to about 20,000 wild rhinos, more than 80 percent of the world’s population. About one-third of the animals are owned by private breeders. Since 2008, more than 7,000 rhinos have been hunted illegally, with 1,028 killed in 2017, according to the South African Department of Environmental Affairs.

Capt. Mali Govender of the Eastern Cape police service confirmed the deaths and said that the remains had been sent for forensic testing. But she said it “was not possible to speculate” how many victims had died.