South Sudan's government has agreed to end hostilities, regional African leaders say.
They said in a statement that they "welcomed the commitment by the Government of the Republic of South Sudan to an immediate cessation of hostilities".
The statement urged Riek Machar, the former deputy president who is accused of orchestrating a plot to overthrow President Salva Kiir, "to make similar commitments".
The East African leaders under a bloc called IGAD were meeting in the Kenyan capital Nairobi.
They said IGAD opposes a violent change of government in the world's newest country and urges Mr Kiir and his rivals to start peace talks before the end of 2013.
Earlier the United Nations said more than 120,000 people have been displaced by continuing violence in South Sudan, and about half are sheltering at UN compounds.
The number of internally displaced people has been rising since fighting started on December 15 in the capital Juba, before spreading across the oil-producing East African nation.
Aid agencies need at least 166 million US dollars (£100 million) to save lives, according to the UN, which has urged South Sudan's leaders to start talks.