South Sudan's government and rebels are to sign a ceasefire shortly, mediators in Ethiopia say.
The talks had been deadlocked over the issue of 11 political detainees, whom the rebels want to be freed before discussing a ceasefire.
In the past week, government forces have recaptured the two main cities under rebel control.
More than 500,000 people have been forced from their homes during the month-long conflict.
What started out as a political dispute between President Salva Kiir and his former deputy Riek Machar on 15 December has escalated into full-scale conflict, with reports of ethnic killings.
Mediators said they expected the rival parties to sign agreements on the "cessation of hostilities and the question of the detainees", at 17:00 local time (14:00 GMT) at the hotel in Ethiopia's capital, Addis Ababa, where the talks have been taking place.