“There is a clear pattern of ethnic persecution, for the most part by government forces, who should be pursued for crimes against humanity,” Mr. Clapham said.
The commission called on the African Union to move immediately to set up a hybrid court combining international and South Sudanese judges, in line with a peace deal it struck with South Sudan in 2015.
“Ultimately this is the only way to stop the rampant devastation of millions of human lives by South Sudan’s leaders,” said Yasmin Sooka, a South African jurist and the panel’s chairwoman.
Sexual violence had become endemic in the latest conflict, the commission said. Among accounts it accumulated was one from a South Sudanese man who said he had been hiding in the bush and returned home to find that government soldiers had gouged out the eyes of his wife with spears when she tried to stop them from raping their 17-year-old daughter. Soldiers had also gang-raped his mother and castrated and beheaded his father, he said.
Another witness told investigators that opposition soldiers had shot and killed his father, raped and killed his mother, and killed all of his brothers and sisters, then castrated him with a knife. He believed they had been attacked because they belonged to the same Dinka ethnic group as South Sudan’s president and his father was loyal to the government.
Sexual violence was used not only to intimidate and humiliate victims, and to force them to flee their homes, but also as a currency of war, with soldiers encouraged to rape in lieu of being paid, Mr. Clapham said. Children are thought to make up a quarter of the victims of sexual violence, the commission said.
Thousands of children, some as young as 12, were recruited to serve as soldiers, the commission found — some were abducted outside their homes; others volunteered to protect themselves and their families. The panel said that children had been forced to kill civilians and loot and had faced corporal punishment if they did not obey.
The commission collected 230 witness statements and 58,000 documents. It said that examining only part of this evidence had helped it identify 38 high-ranking military officers and three state governors responsible for serious rights violations and international crimes.
It will submit a confidential dossier containing those names to the Human Rights Council when it presents the report in March. These individuals “should face prosecution,” the commission said.
As investigators acquired more information, other names could be put forward for prosecutors to investigate. “It’s not a closed list,” Mr. Clapham told reporters in Geneva.
Despite deep international frustration over the failure of South Sudan’s leaders to implement the 2015 peace agreement or a December 2017 cease-fire, Mr. Clapham also expressed confidence in the African Union, saying it was determined to go ahead with setting up the court and had already begun preparations.
“The time is up,” he said. “The issue now is to get the South Sudanese and the African Union to agree on this quickly.”