Eight boys have died and three are in hospital after botched circumcisions in the South African province of Mpumalanga, officials say.
The teenagers were at an initiation school in the town of Kwamhlanga.
One of the initiates died in hospital and the seven others were found by health officials dead at the school.
Circumcision is a traditional rite of passage for many boys in South Africa, where authorities have long campaigned to stop botched initiation ceremonies.
Although it is unusual for so many boys to die at the same time, deaths from circumcisions are occasionally reported in South Africa, where blunt, un-sterilised knives are sometimes used.
'Excessive blood loss'
Fifteen initiates were admitted to Kwamhlanga Hospital since Saturday, Simphiwe Kunene, of the Mpumalanga health department, told the South African Press Association news agency.
Eleven were later discharged and three were still being treated, but one died.
Seven more bodies were found at the initiation school when forensic pathology officials were called, bringing the total fatalities to eight.
"At the moment, we are not in position to say what killed the young men, but the three who are still in the hospital had shown signs of excessive loss of blood," another health department spokesman Mpho Gabashane told South Africa's Times newspaper.
Mr Kunene told Sapa that health officials were working with traditional leaders to ensure resources were available that could prevent further loss of life.
In 2001 the government passed an act requiring a licence from a medical officer for each circumcision, but traditional leaders said that infringed community rights.
The BBC's Mpho Lakaje in Johannesburg says the tradition is also sometime exploited by those looking to make money by setting up illegal initiation schools.