The preceding Peacekeeping Forces all related to the Arab/Israeli wars. The other Middle East United Nations peacekeeping operation was in Yemen. Civil War broke out in that country in September 1962 after the army overthrew the monarchy and proclaimed a republic. The civil war quickly became an international issue with Egypt supporting the royalists. A United Nations peace initiative eventually led to the establishment of the United Nations Yemen Observation Mission (UNYOM). A demilitarised zone was to be established to a distance of 20 kilometres on each side of the Saudi Arabia-Yemen border with UNYOM observers stationed there to check on the observance of the terms of disengagement. Australian observers joined the mission when it was formed and stayed until November 1963 when the personnel and equipment requirements were reassessed. UNYOM was finally withdrawn on 4 September 1964 without having achieved its aim but relations between the parties improved shortly after withdrawal of UNYOM and the problems were resolved. UNYOM is listed in Schedule 3 VEA as commencing on 1 January 1963 although the mission did not commence until 4 July 1963.