The fighting erupted Wednesday evening and continued Thursday at a U.N. civilian protection site in the northeastern city of Malakal, officials said. Doctors Without Borders teams reported treating dozens of wounded.
Youths from the Shilluk and Dinka ethnic groups fought using small arms, machetes and other weapons, the United Nations Mission in South Sudan said in a statement condemning the violence
U.N. police used tear gas to disperse the crowd, the mission said. Officials released photos showing smoke billowing in the sky above the compound.
The site is one of six U.N. bases housing nearly 200,000 people displaced by violence in the country, according to the mission. More than 47,000 people have taken shelter at the Malakal site. The number of people living there more than doubled last year, Doctors Without Borders said
Many of them came from areas where there had been no aid for months, the organization said, and most arrived without any possessions.
It's a place where people go seeking protection, said Marcus Bachmann, coordinator of Doctors Without Borders projects in South Sudan.
"This should be a sanctuary respected by all parties," he said.
U.N Secretary-General Ban Ki-moon noted that "any attack directed against civilians, U.N. premises and peacekeepers may constitute a war crime," his spokesman said in a statement
"He warns all parties against stoking ethnic disputes and calls on them to refrain from any actions or statements that could further escalate the situation," the statement said.
The statement also called on South Sudan's leaders to implement a peace agreement to end fighting.
, the world's newest country, has been embroiled in one of the world's most brutal -- and under-reported -- conflicts since December 2013.
Earlier this week South Sudan's President reinstated his vice president
as part of a peace deal to end the country's two-year civil war.