The United Nations Refugee Agency (UNHCR) has expressed concern over the escalation of armed conflict in South Sudan's Upper Nile state, which has displaced at least 20,000 people since August, some of whom have been forced to flee for their lives up to four times. In a statement Wednesday, the UN agency warned that at least 3,000 people have already fled to neighboring Sudan, further exacerbating the refugee crisis in South Sudan, the largest in Africa.