United Nations Secretary-General Antonio Guterres is urging South Sudan's leaders to end a civil war that has killed tens of thousands and displaced millions of people.
After touring a refugee reception area in northern Uganda, Guterres said Thursday that "the leaders of South Sudan have not deserved the people they have."
Guterres visited ahead of a U.N.-backed summit in Uganda that is aimed at raising global awareness of the world's fastest-growing refugee crisis.
More than 900,000 refugees from South Sudan are sheltering in Uganda, most of them women and children. Most have arrived in the past year.
Uganda and the U.N. say $8 billion is needed to help the refugees and host communities over the next four years.
The European Union on Thursday announced 85 million euros in aid.