The remark Sunday by U.N. Deputy Secretary General Jan Eliason came one day after the presidents of the two countries met on the sidelines of the African Union summit in Ethiopia in their first meeting since a border dispute brought their countries close to war in April.
A senior South Sudanese official confirmed the meeting but said he was not allowed to further discuss the talks.
South Sudan broke away from Sudan last year after a referendum, but violence has flared along the border. South Sudan shut down its oil industry after accusing Sudan of stealing oil that it is shipped through Sudan's pipelines. They continue to be at odds over oil rights and their border.