The President of South Sudan, Salva Kiir, was scheduled to sign a peace deal with rebel leader Riek Machar on Wednesday, to end months of bloody civil war.
Monday of last week, the rebel leader and former Vice President Riek Machar, signed the peace deal but Mr Kiir rejected signing it.
The UN Emergency Relief Coordinator Stephen O’ Brien alerted UN Security Council members in a meeting, saying that situation has become progressively worse and added that he has reports of atrocities being committed, including victims who were burnt alive during the war.
#SouthSudan: Atrocities reported incl. rampant killing, rape, abduction, arson & horrific acts like burning people alive inside their homes
— Stephen O'Brien (@UNReliefChief) August 25, 2015
"The scope and level of cruelty that has characterized the attacks against civilians suggests a depth of antipathy that goes beyond political differences," he said.
Also, current president of the UN Security Council, Nigerian Ambassador Joy Ogwu, said the council was united and will "act immediately" towards South Sudan peace deal.
"We all agree on measures to be taken that anybody who is found culpable will be held accountable," she said.
Kiir asked for another 15 days to consider the peace deal brokered by regional leaders, shrugging off pressure to meet a Monday deadline.
South Sudan plunged into civil war in December 2013, when a political crisis sparked fighting between forces loyal to Kiir and rebels allied with his former deputy Riek Machar. The conflict has reopened ethnic fault lines that pit Kiir's Dinka people against Machar's ethnic Nuer's.