On 29 May 1948, the United Nations Security Council, in its resolution 50 (1948) called for a cessation of hostilities in Palestine and established the first peacekeeping mission headed by a UN Mediator with the assistance of a group of military observers to be known as the United Nations Truce Supervision Organization (UNTSO). UNTSO is mandated to observe and maintain the unconditional ceasefires and assist the parties to the 1949 Armistice Agreements in the supervision of the application and observance of the terms of those Agreements. UNTSO’s mandate covers five countries, including Egypt, Israel, Jordan, Lebanon, and the Syrian Arab Republic. This position is located in the United Nations Truce Supervision Organization (UNTSO) in Jerusalem. Under the general management of the Chief Security Officer, the Security Officer at the FS-4 Level reports to the Supervisor of the Special Investigations Unit (SIU) on all issues related to security investigations and other fact-finding activities in UNTSO AOR and to Chief SIOC on operations security related issues.