Gruesome violence seen in South Sudan conflict, including beheadings, sex attacks: officials

FILE - In this Sunday, Jan. 12, 2014 file photo, South Sudanese government forces ride on a vehicle through the still-smoldering town, after government forces on Friday retook from rebel forces the provincial capital of Bentiu, in Unity State, South Sudan. U.N. Secretary-General Ban Ki-moon on Wednesday, Jan. 15, 2014 strongly condemned the commandeering of humanitarian vehicles and the theft of food and other desperately needed aid by government and anti-government forces in violence-torn South Sudan. (AP Photo/Mackenzie Knowles-Coursin, File) (The Associated Press)

FILE - In this Monday, Dec. 30, 2013 file photo, a United Nations armored vehicle travelling in convoy with a truck passes displaced people walking towards the U.N. camp where they have sought shelter in Malakal, South Sudan. U.N. Secretary-General Ban Ki-moon on Wednesday, Jan. 15, 2014 strongly condemned the commandeering of humanitarian vehicles and the theft of food and other desperately needed aid by government and anti-government forces in violence-torn South Sudan. (AP Photo/Ben Curtis, File) (The Associated Press)

Officials in South Sudan say the U.N. has gathered evidence of gruesome attacks being carried out in the country's month-old conflict.

The officials say that some victims of ethnic-based attacks have been bound and others beheaded. Victims have also told The Associated Press that attackers have forced them to participate in sex acts with family members.

The U.N.'s assistant secretary-general for human rights, Ivan Simonoviae, is scheduled to give a news conference Friday. The two officials who detailed the violence insisted on anonymity because they weren't authorized to release the information.

Human Rights Watch, in a report Thursday, said the worst ethnic-based attack took place in mid-December, when 200 to 300 men from the Nuer ethnic group were jammed into a room that gunmen fired into, killing nearly everyone.