On 29 November 1947, the United Nations General Assembly adopted Resolution 181 on "the future constitution and government of Palestine" setting forth a "Plan of Partition with Economic Union".

It called for the creation of Arab and Jewish states no later than 1 October 1948, with Jerusalem as corpus separatum under an international regime to be administered by the U.N. with the Trusteeship Council being the designated body in this regard.

It also requested the government of the U.K., as the Mandatory Power, to supervise the execution of those measures and to keep the Security Council and the General Assembly informed on the situation in Palestine.

[13] The General Assembly then convened for its second special session between 16 April to 14 May 1948, during which it considered a working paper submitted by the United States (U.S.) on the question of the "Trusteeship of Palestine", which was opposed by the Union of Soviet Socialist Republics (U.S.S.R.) as well as the Jewish Agency.

After receiving proposals from the Trusteeship Council, the assembly adopted Resolution 187 (S-2), recommending to the Mandatory Power the appointment of a Special Municipal Commissioner for Jerusalem.

[20] According to the United Nations, "following the wars of 1948, 1956, 1967 and 1973, [UNTSO's] functions...[have evolved]... in the light of changing circumstances, but they [have] remained in the area, acting as go-betweens for the hostile parties and as the means by which isolated incidents could be contained and prevented from escalating into major conflicts.

United Nations military observers (UNMOs) remain in the Middle East to monitor ceasefires, supervise armistice agreements, prevent isolated incidents from escalating and assist other UN peacekeeping operations in the region.

[27] On 29 May 1948, UN Security Council Resolution 50 (1948), called for a cessation of hostilities in Palestine and decided that the truce should be supervised by the Bernadotte with the assistance of a group of military observers.

Bunche, Chief of the UN Mission in Palestine, in his letter to the Israeli Foreign Minister Moshe Shertok wrote that the incident was "an outrage against the international community and an unspeakable violation of elementary morality.

His [Bernadotte's] safety, therefore, and that of his Lieutenants under the ordinary rules of law and order was a responsibility of the Provisional government of Israel whose armed forces and representatives control and administer the area.

"[36] The Provisional Government of Israel did not submit the report to the Security Council or to the Acting Mediator regarding the progress of the investigation into the assassination of Count Bernadotte.

On 11 August 1949, it was decided by the Security Council that the mediator's function had been completed and that the role in observing the ceasefire should be passed to the Chief of Staff of the UNTSO.

[38] In 1949, UNTSO military observers remained to supervise the 1949 Armistice Agreements between Israel and its Arab neighbours, which were for many years the main basis of the uneasy truce in the whole area.

UNTSO's activities have been and still are spread over territory within five States, and therefore it has relations with five host countries – Egypt, Israel, Jordan, Lebanon and Syrian Arab Republic.

[21] The period from August 1949 to June 1956 was initially chaotic but quickly settled into a routine of complaints on the Jordanian, Egyptian, Syrian and Lebanese fronts.

The GAAs had been hastily prepared in anticipation of an early peace along the lines of the 1947 Partition Plan and the primary concern was an end to the bloodshed at the earliest opportunity.

In the case of the Egyptian Armistice line Israel forces carried on with a push south[40] arriving at Umm Rashrash (Eilat) in March[41] after the Egyptian-Israel GAA of 24 February 1949.

Articles VII and VIII of the Egypt-Israel GAA established a Demilitarized Zone (DMZ) centred on El-Auja and forbade the presence of armed forces.

[57] After the 1956 War (often referred to as the Suez Crisis),[58] UNTSO greatly assisted the establishment of the United Nations Emergency Force (UNEF); in large measure the result of diplomatic efforts of the UN Secretary-General Dag Hammarskjöld and a proposal from Canadian minister of external affairs Lester Pearson, by providing a group of trained military personnel for peacekeeping and emergency operations to UNEF.

On 6 March 1957, General Burns was able to report to the Secretary-General of the UN that the "United Nations Emergency Force troops are now in position in all camps and centres of population in Gaza Strip".

[64] The staged withdrawal of Israeli forces from the Gaza Strip, with the exception of an Israel troop unit at Rafah camp, at 0400 GMT on 7 March 1957 was carried out according to plan and without incidents.

By agreement, that last Israel element was withdrawn by 1600 GMT on 8 March and a full Israeli withdrawal from the Sharm al Shaikh area was effected at the same time.

[71] After heavy fighting broke out between Israel and Syria in the DMZ, the Security Council in Resolutions 92 (1951) and 93 (1951) of 8 and 18 May 1951 called upon the parties to cease fighting and endorsed the request of the Chief of Staff of UNTSO that the Israeli company involved be instructed to cease all operations in the DMZ until such time as an agreement is arranged through the Chairman of the MAC for continuing its project.

[75][76] In Resolution 111 (1956) of 19 January 1956, the Security Council dealt with the confrontation which had escalated following interference by the Syrian authorities with legitimate Israeli activities on Lake Tiberias.

It also noted that in violation of the provisions of the General Armistice Agreement concerning the DMZ, the Zone had been crossed by the Israeli forces that entered Syria.

It determined that an Israeli attack on 16–17 March had been a flagrant violation of the previous resolution (111), and called on Israel scrupulously to refrain from such action in the future.

[86] Four unarmed UN peacekeepers from Austria, China, Finland and Canada were killed during an Israeli air strike on 25 July 2006, which struck a UN OP at Khiam.

[91] In 2020, the following nations contributed personnel: Argentina, Australia,[92] Austria, Bhutan, Belgium, Canada, Chile, the People's Republic of China, Denmark, Estonia, Finland, Fiji, Gambia, Ireland,[93] India, Nepal, the Netherlands, New Zealand, Norway, Poland, Russia (formerly the Soviet Union), Serbia, Slovenia, Slovakia, Sweden, Switzerland and the United States.

All military observers are seasoned officers of the rank of captain or major coming from all branches of service in their respective countries armed forces.

[62] Each outstation maintains "a number of observation posts on each side of the Area of Separation (AOS) that was put in place as part of the 1974 Disengagement Agreement between Syria and Israel following the 1973 Yom Kippur War.