JUBA, Sept. 9 (Xinhua)-- South Sudan's exiled rebel leader Riek Machar arrived in Juba on Monday for face-to-face talks with President Salva Kiir.

Machar, Sudan People's Liberation Movement-In-Opposition (SPLM-IO) leader who has been under house arrest since 2016 is accompanied by Mohamed Hamdan Daqlu, deputy head of Transitional Military Council and a contingent of 70 officials.

President Kiir and Machar are expected to discuss and reevaluate progress and challenges facing the revitalized peace deal they signed in September 2018 in Ethiopia to end more than five years of conflict.

The warring parties failed to form the much-awaited transitional unity government in May and both agreed to a six-month extension with only three months remaining amid regional and international concern over delays.

They are also expected to speed up implementation of outstanding issues which include cantonment of forces, demarcation of tribal boundaries and determining the number of states before forming the unity government in November.

South Sudan descended into conflict in December 2013 after President Salva Kiir sacked his deputy Riek Machar leading to fighting between soldiers loyal to both leaders.

The conflict killed tens of thousands and displaced millions both internally and externally.

A peace deal signed in 2015 collapsed after outbreak of renewed violence in July 2016 forcing Machar to flee the capital.

Under the 2018 peace deal Machar will take up one of the four vice presidency positions in the transitional government.