The expected return of South Sudan’s rebel leader Riek Machar to the capital, Juba, has been postponed for logistical reasons, a spokesman said.
He was due to take up the post of first vice-president, a key part of the peace process aimed at ending more than two years of civil war.
Mr Machar fled Juba at the start of the conflict in December 2013.
More than two million people have been displaced and tens of thousands killed in the fighting.
Rebel spokesman William Ezekiel told journalists waiting for Mr Machar at Juba’s airport that the trip had been postponed until Tuesday.
He said that the rebels were still committed to the peace process agreed last August, but was not specific about the nature of the logistical problems.
The government has not yet responded to the failure of the rebel leader to arrive.
The civil war broke out over tensions between President Salva Kiir and Mr Machar, who was sacked as vice-president in July 2013.
Then, in December 2013, Mr Machar was accused of trying to organise a coup.
e denied the accusation but it set off a round of tit-for-tat killings, which developed into a full-blown conflict.
The two sides have been slow to implement the peace deal, with reports of ceasefire violations on both sides.