UN Secretary General Ban Ki-moon arrived in Juba on Thursday to try and revive a shaky peace deal that has so far failed to end South Sudan's two-year-old civil war.
Ban was greeted at Juba's airport by Foreign Minister Barnaba Marial Benjamin before being driven to see President Salva Kiir whose dispute with rival Riek Machar triggered civil war in December 2013.
The UN chief is expected to visit mainly humanitarian disaster operation areas. Of particular interest to Ban is the UN House in Juba, believed to be hosting large numbers of the displaced populations.
He will hold discussions with community leaders representing thousands of civilians sheltering in the protection site.
Fighting has continued despite an August peace deal with at least 18 killed in the latest incident in the north-eastern town of Malakal last week when government soldiers participated in an attack on a UN-protected camp for nearly 50,000 civilians seeking shelter from the war.
Ban will also hold talks with President Salva Kiir, on humanitarian related problems as well as the implementation of the peace agreement and formation of the interim government.
The UN Office of Humanitarian Coordination recently warned of a humanitarian catastrophe if peace failed to prevail in South Sudan.
The conflict has been marked by rights violations and attacks on civilians with children murdered or recruited into militias, women and girls abducted into rape camps and used as sex slaves, multiple ethnic massacres, attacks on UN bases and aid workers.
An African Union investigation published last year found evidence of forced cannibalism and concluded that war crimes had been committed.
A succession of UN rights reports have also found evidence of war crimes.
South Sudanese leaders were under international pressure to form the Government of National Unity and commit themselves to implement the peace deal.