A delegation of South Sudan's rebels has returned to the capital after two years of exile to start implementing a peace agreement signed four months ago.

Paul Kordit, the head of the government's reception committee said Monday that 15 members of a 150-person advance team landed in South Sudan's capital, Juba, from Gambella, Ethiopia, to start work to make the peace deal a reality.

South Sudan's civil war started on December 15, 2013 after a skirmish in a barracks in Juba between soldiers loyal to President Salva Kiir, an ethnic Dinka, and troops who support Riek Machar, who is of the Nuer tribal group. The United Nations says tens of thousands have been killed.