Officials have documented 217 cases of sexual violence in South Sudan's capital during last month's outbreak of fighting, most of them committed by government security forces, the United Nations human rights chief said Thursday, August 4, according to the Associated Press.

Information so far indicates that displaced ethnic Nuer women were the most targeted, Zeid Ra'ad al-Hussein said in a statement.

Witnesses and aid workers have told The Associated Press that government soldiers raped or gang-raped dozens of women and girls just outside the main U.N. camp in the capital, Juba, where thousands of mostly Nuer people have taken shelter from the fighting.

South Sudan's civil war that started in December 2013 has long raised fears of targeted ethnic violence. The Nuer, who are the same ethnicity as rebel leader and former vice president Riek Machar, fear attacks by government forces who are mostly ethnic Dinka, the same as Machar's rival, President Salva Kiir.

Zeid said the 217 documented cases of sexual violence occurred between July 8 and July 25.

He also said some civilians were killed by government forces "who appear to have specifically targeted people of Nuer origin."

The U.N. has documented the deaths of at least 73 civilians so far, but that toll "may in fact turn out to be much higher," the human rights chief said.

Zeid said tensions in Juba remain "very high" and violations continue to take place throughout the East African country.