More than 52,000 South Sudanese fled to Uganda in January amid continued fighting that risks turning into a mass atrocity, the UN's special adviser on genocide prevention said Tuesday.
Many of those who have fled reported killings of civilians, the destruction of homes, sexual violence, and the looting of livestock and property, said Adama Dieng.
"President Salva Kiir has made a commitment to end the violence and bring about peace, yet we still see ongoing clashes, and the risk that mass atrocities will be committed remains ever-present," he said in a statement.
Dieng said there was particular concern about the situation in Kajo-Keji, located south of the capital, Juba, where UN peacekeepers have faced access restrictions and civilians are fleeing en masse.
South Sudan descended into civil war in 2013, less than two years after gaining independence. The conflict arose from a rivalry between President Salva Kiir, an ethnic Dinka, and his former deputy Riek Machar, an ethnic Nuer. A peace process and a power sharing agreement have failed to take hold.
In December, the UN warned the conflict risked turning into a genocide.
Fighting has displaced more than 1.85 million people internally and sent another 1.4 million fleeing to neighboring countries. About half the population of 12 million people is in need of humanitarian aid - a number that aid agencies say could rise by 20 or 30 percent this year.
The UN warned earlier this month that fighting and disrupted humanitarian activities would likely contribute to extreme levels of food insecurity in South Sudan this year.