JUBA (Reuters) - South Sudan's President Salva Kiir has ordered his country's army to pull out of a buffer zone on the border with Sudan to set up a demilitarized area, South Sudan's army spokesman said on Monday.

"The Sudan People's Liberation Army has received instructions from the commander in chief of the SPLA, President Salva Kiir, to effect the withdrawal from the proposed safe demilitarized buffer zone," South Sudan armed forces spokesman Philip Aguer said, adding that the withdrawal would take about two weeks.

The two sides have previously failed to fully implement a range of border and other disputes.

(Reporting by Hereward Holland; Writing by Alexander Dziadosz; Editing by Kevin Liffey)