A new report from Amnesty International says government forces in South Sudan deliberately killed and raped citizens while U.N. forces failed to act during clashes in the capital in July.
The five days of fighting between forces loyal to President Salva Kiir and loyalists of then-first vice president Riek Machar left at least 270 people dead and displaced 36,000 from their homes.
The report describes how government forces targeted people based on ethnicity and perceived political loyalties.
"South Sudanese government troops killed men from the Nuer ethnic group, raped women and girls, and carried out a massive campaign of pillage," said Joanne Mariner, Amnesty's senior crisis response adviser.
Amnesty also reports that U.N. peacekeepers did little to stop the attacks on civilians.
Gang rape allegations
One Nuer woman said she was raped by five government soldiers in front of a U.N. base in the Jebel neighborhood. She said U.N. peacekeepers and private security guards could see the attack, but did not come to her aid.
The international rights group calls on the international community to acknowledge the atrocities being committed by the South Sudanese government and stop the flow of weapons into the country.
"The international community must impose a comprehensive arms embargo or risk being seen as complicit in these violations," Mariner said.
There was no immediate comment from the government of South Sudan or the U.N. peacekeeping force in South Sudan, UNMISS.
Also on Tuesday, the U.N. High Commissioner for Human Rights (OHCHR) expressed its concern for the "alarming rise in hate speech and incitement to violence against certain ethnic groups" in South Sudan.
Letters "with graphic warnings of violence against Equatorians" have been left outside offices in Juba, and ethnic Dinka youth groups have threatened to "eliminate" Equatorians, OHCHR spokeswoman Ravina Shamdasani said.
"The delicate situation in South Sudan makes the hateful rhetoric between Dinkas and Equatorians highly dangerous, and this could result in mass atrocities if not reined in," she told a press briefing in Geneva.
South Sudan erupted in a civil war just two and half years after gaining independence in 2011, when President Salva Kiir accused his former deputy Riek Machar of plotting a coup d’etat.
Machar returned to the capital, Juba, this year after a peace deal was negotiated in 2015, but fresh fighting erupted outside the presidential palace on July 8 while Machar was inside.