Direct talks aimed at ending weeks of violence in South Sudan are due to begin.
They would come a day after delegations from the warring parties met mediators in the Ethiopian capital, Addis Ababa.
Ethiopia's Foreign Affairs Minister Tedros Adhanom said the initial meetings had been "fruitful".
Continued fighting between supporters of President Salva Kiir and his sacked deputy, Riek Machar, has killed at least 1000 people since 15 December.
The US has said it remains committed to ending the violence, despite evacuating most of its embassy staff from Juba.
"Even as we draw down our personnel, the United States remains deeply and actively committed to supporting regional and international efforts to end the violence in South Sudan," said State Department deputy spokeswoman Marie Harf.
More than 180,000 people have been displaced in the conflict. Aid workers say many are living without shelter, clean water or sanitation.
The violence has been continuing, with reports of heavy fighting on the outskirts of the rebel-held city of Bor, in Jonglei state, on Friday.
The government said its troops were attempting to recapture both Bor and the city of Bentiu, in the northern state of Unity. At the same time, rebel forces said they were advancing on the capital, Juba.
Delegates from both sides began arriving in the Ethiopian capital on Wednesday but talks were delayed until the full negotiating teams had arrived.
The BBC reports the rival teams were in the same hotel but on Friday had only held talks with mediators, who were preparing the ground for direct negotiations.
The Ethiopian minister of foreign affairs said face-to-face talks would follow.
