United Nations Secretary-General Ban Ki-moon is in South Sudan to push for an end to fighting between government and rebel forces.
Mr. Ban's one-day trip to Juba on Tuesday includes talks with President Salva Kiir and a visit to the U.N. mission's Tomping compound, where he will meet with community leaders from the thousands of people who have sought protection there.
His visit comes a day after U.S. Secretary of State John Kerry warned of sanctions and other possible consequences if South Sudan's government and rebel forces do not commit to peace talks.
Kerry secured a commitment from Mr. Kiir to participate in negotiations, and said Monday that rebel leader Riek Machar has a "fundamental decision" to make in the way he proceeds.
The rebels and government signed a cease-fire agreement in January, but fighting has continued.
Months of violence across South Sudan has led to thousands of deaths and driven more than 1.25 million people from their homes. Tens of thousands are sheltering in U.N. bases throughout the country.