Wrapping an arm around her stomach, the young woman hung her head and recounted the day in early November when she and a friend were bound, dragged into the bush and raped by four men with guns."My body hasn't been the same since," the 18-year-old said. The men attacked during an hours-long walk home to the South Sudan village of Nhialdiu. "I was crying and screaming but I was so far from the village that no one could hear me," she told The Associated Press, which doesn't identify survivors of sexual assault.Shock and outrage followed when the medical charity Doctors Without Borders announced that 125 women and girls had been raped, whipped and clubbed over 10 days last month in a dramatic spike in sexual violence. "Horrific," the United Nations secretary-general said. They were attacked as they made the long walk to a food distribution site in Bentiu, in Unity state.In an exclusive look at the aftermath, the AP joined a UN peacekeeping patrol where the attacks occurred as humanitarians, rights groups and South Sudan's government scrambled to find out more.Rape has been used widely as a weapon in South Sudan. Even after a peace deal was signed in September to end a five-year civil war that killed nearly 400 000 people, humanitarians have warned of higher rates of sexual assault as growing numbers of desperate people try to reach aid. While some aid groups have quietly questioned whether all 125 people in the Doctors With Borders report were raped, they do not dispute that the problem has become grave.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook. The 18-year-old was not included in that report, and the real toll of sexual assault is not known.Joining the UN patrol on Friday, the AP traveled the potholed road where the recent assaults took place. Shrouded by trees and elephant grass, some stretches provide cover for perpetrators to lurk.Several local women said the violence is escalating.Nyalgwon Mol Moon said she was held at gunpoint last month while two men in civilian clothes, their faces covered, stole her clothes, her shoes and the milk she meant to sell at market. Standing beside the road, pointing to her borrowed, oversized sneakers, she said she now tries to take alternative routes on her weekly walks to Bentiu.She has no other choice. Food in Nhialdiu and nearby villages is scarce. Most people could not cultivate last season because of fighting and too much rain. Many rely on monthly aid from the UN's World Food Programme.That means a walk of almost 40km to Bentiu town. Unable to carry the heavy rations back in one trip, most women leave some behind with relatives and make several journeys throughout the month.Some said they make the 11-hour trek at least six times.Alarmed by the sexual assaults, the World Food Programme said it is prepared to bring distribution points closer to communities. The UN is now clearing the road from Bentiu to Nhialdiu of debris to make access easier.No one has taken responsibility for the wave of assaults that the UN and African Union have condemned as "abhorrent" and "predatory".Habouring criminals South Sudan's government has acknowledged the assaults occurred in areas it controls, on the road between Nhialdiu and Bentiu and in surrounding villages. But it blames them on "unregulated youth" who fought alongside warring factions before the peace deal, Laraka Machar Turoal, deputy governor of Northern Liech state that was once part of Unity, told the AP.Youth who were never officially integrated with armed groups have been left idle, guns in hand, to take what they want by force, Turoal said.South Sudan's government has called on all sides to demobilise the youth. It said it has deployed troops to areas in Unity state suspected of harbouring criminals.And yet the army in Nhialdiu has not detained anyone in the assaults and denies responsibility for finding the perpetrators, said John Dor, army commander for the area. He said they took place far from town, outside his jurisdiction.But several local people said they knew of attacks in villages less than 15km from the army base. Some who were attacked at gunpoint said they believe the armed youth are affiliated with government troops. The government has done nothing so far to stop the violence, one woman explained.The UN, which has increased patrols, is pushing South Sudan's government to take more responsibility. The UN Security Council in a statement on Saturday noted its willingness to impose sanctions on those who threaten the peace, including by sexual violence.Peace deal "They're obliged to make sure everyone's protected ... it's not enough just to sit in one place and not be involved," said Paul Adejoh Ebikwo, the UN mission's senior civil affairs officer in Bentiu.Unity state was one of the hardest-hit areas in the civil war, and Bentiu has changed hands several times. Government and opposition forces remain at odds, even as factions across the country try to reconcile. A meeting on Thursday to build trust was canceled because the parties couldn't agree on a place to meet, said the independent monitoring group charged with overseeing the peace deal's implementation.Meanwhile, many women and girls are terrified.Cautiously peering through the trees, several hesitantly emerged from the bush, inching toward the side of the road."We're walking here because we're scared of coming on the main path," said Nyachieng Gatman. Three days ago, she said, she met a breast-feeding mother and young girl who had been raped in a nearby town.Standing beside her, 11-year Anchankual Dood lowered her heavy bag of grain and gulped from a bottle of water."It's a long distance to go and come from Bentiu," the girl said. "But we do it because we need food and because we're suffering."