United Nations Secretary-General Ban Ki-moon is in South Sudan to push for an end to violence that has displaced more than 1.2 million people.
The U.N. chief flew into the capital, Juba, on Tuesday and met with President Salva Kiir, who, according to the U.N. mission, reiterated his commitment to meeting with rebel leader Riek Machar.
Mr. Ban also visited the U.N. mission's Tomping base, where he met with community leaders representing the thousands of civilians who have sought protection there.
Mr. Ban's 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.
The two sides signed a cease-fire agreement in January, but fighting has continued.
The U.N. refugee agency says 11,000 South Sudanese have crossed the border into Ethiopia since Saturday, fleeing clashes between government and rebel troops in the Upper Nile region.
The agency says overall, 315,000 South Sudanese have fled to neighboring countries since violence erupted in December, while more than 920,000 others are displaced internally. Tens of thousands are sheltering at U.N. bases across the country.