Haley had been visiting a UN-operated camp for displaced people, the Associated Press reports. The political demonstration was being held to oppose South Sudanese President Salva Kiir, the report says.
UN security personnel used tear gas to force the more than 100 demonstrators to break up and leave, a camp worker said.
Haley issued a warning to Kliir during the visit that the "hate and the violence that we are seeing has to stop… I let him know the US is at a crossroads, and every decision going forward was going to be based on his actions."
— Nikki Haley (@nikkihaley) October 25, 2017
Armed groups loyal to Kliir and Riek Machar have clashed for years in a civil conflict that has led to the displacement of millions of people within the nation. Haley said Kliir's military has used child soldiers and some of its members engage in rape.
The US has poured more money in South Sudan for humanitarian assistance than any other nation, with at least $11 billion already committed, the Hill reports. Haley expressed displeasure at what she saw in South Sudan, stating, "This is not what we thought we were investing in. What we thought we were investing in was a fair, free society where people could be safe and South Sudan is the opposite of that."