The head of the United Nations Children's Fund (UNICEF) on Thursday has called for a halt to the unspeakable violence against children in South Sudan involving the castration of boys who were left to die and the gang rapes and killings of girls as young as 8.Children were also tied together and their throats were slit; others were thrown into burning buildings. The attacks that Anthony Lake, executive director of Unicef, has described left 129 children dead within a three-week period in May alone.Lake said the children were killed in the conflict-torn country's Unity State and said survivors witnessed harrowing violence.The organization reported that the children in South Sudan were experiencing "a new level of brutality.""In the name of humanity and common decency this violence against the innocent must stop," said Lake.Lake warned that an estimated 13,000 children have been recruited as child soldiers in the course of the civil conflict which broke out in December 2013 when a power struggle between President Salva Kiir and his former deputy Riek Machar turned violent.Successive ceasefires aiming to end the conflict, which has ethnic undertones, have been unable to stop the fighting, which has killed tens of thousands and displaced nearly 2 million people.