Fresh reports of atrocities in war-torn South Sudan emerged Wednesday as negotiators tried to break a deadlock in talks in Ethiopia aimed at ending weeks of brutal conflict in the young nation. Thousands have been killed and half a million civilians forced to flee the fighting between troops loyal to President Salva Kiir and rebels allied to his sacked deputy Riek Machar. The United Nations says atrocities have been committed by both sides, including mass killings, sexual violence and widespread destruction. A report released Wednesday by South Sudan's presidency detailed devastation in the town of Bor while it was under rebel control, accusing the rebels of executing 127 patients in the hospital. Bor, which has swapped hands four times in the conflict, was left with corpses littering the streets and scores of buildings razed to the ground. The government report could not be independently verified, but civilians in Bor have recounted to AFP grim stories of how the rebels gang-raped and murdered patients in the town's hospital. "Towns such as Malakal, Bor and Bentiu have been reduced to rubble, and there is nothing to salvage," presidential spokesman Ateny Wek Ateny said in a statement. Stalled ceasefire talks in Ethiopia are being mediated by the East African regional bloc IGAD, with the two sides meeting face to face again on Wednesday afternoon. Fighting has spiralled into ethnic killings between members of Kiir's Dinka people -- the country's largest group -- and Machar's Nuer. Many fear the conflict has spun out of the control of the politicians who sparked it. "More important than signing is the work we do after... as attitudes on the ground will not change with the stroke of a pen," rebel delegate Mabior Garang said late Tuesday. Getachew Reda, spokesman for Ethiopian Prime Minister Hailemariam Desalegn who is hosting the talks in Addis Ababa, admitted that talks were slow, but also insisted that "so far the progress is very good". "There has been so much badblood involved now, and there is so much misunderstanding and hard feelings already for the last month, so it would be foolhardy to expect the two parties to come together just at the snap of a finger," Getachew told AFP. "Yes, there are people who are suffering... but as far as the pace of negotiations go, as much as we regret the fact that the cessation of hostilities is somewhat late, we cannot say that the situation is hopeless." A draft IGAD ceasefire accord, seen by AFP and presented to peace delegates meeting in Addis Ababa, notes the "scale of human suffering" since fighting broke out on December 15. The ceasefire proposal specifically highlights that both sides must "refrain" from attacking civilians, carrying out summary executions and using child soldiers as well as committing "rape, sexual abuse and torture". Government forces this week took full control over Malakal, one of most bitter flashpoints since fighting erupted, and the last major settlement under rebel control. Rebels are reported to remain powerful and in control of large areas of the countryside, and battles continue. Kiir's spokesman also rowed back on comments made on Monday, when he lashed out at the United Nations accusing it of wanting to create a "parallel government". UN chief Ban Ki-moon had earlier expressed alarm at reports that government figures and troops threatened UN staff when they tried to enter a peacekeepers' compound to which thousands of civilians had fled. But Ateny stressed that Kiir was "resolute to see the UN and all international organisations being respected and accorded protection unreservedly."