The Security Council welcomed the withdrawal of military troops of Sudan and South Sudan from the region but said full withdrawal must include other forces Sudan reportedly has in there, Voice of America reported.
U.N. officials have said Sudan still has armed police in the region.
In a statement, the 15-member Security Council said, "Members of council emphasized that full withdrawal must include police forces, including oil police."
The council said it welcomed the resumption of talks Tuesday between Sudan and South Sudan and urged both countries to "keep momentum" in talks on a May 2 council resolution condemning cross-border violence between the countries and calling on both to end fighting, withdraw forces and begin talks.
The talks began in Addis Ababa, Ethiopia, with initial reports of slow progress, VOA said.
U.S. Ambassador Susan Rice said there had been progress about a month after adoption of the resolution but pointed to a humanitarian crisis in Sudan's Southern Kordofan and Blue Nile provinces. Rice reported "dire, acute malnutrition" among refugee children and said "the numbers are skyrocketing."
She said "there has been no progress in terms of the government of Sudan allowing open humanitarian access, including into rebel areas."
The Sudan Tribune reported Sudanese and South Sudanese negotiators have presented proposals on a schedule for the talks.