ROK-US Combined Forces Command

The United Nations Command (UNC) is the unified command structure for the multinational military forces supporting South Korea (the Republic of Korea or ROK) during and after the Korean War. After troops of North Korea invaded South Korea on June 25, 1950, the United Nations Security Council adopted Resolution 82 calling on North Korea to cease hostilities and withdraw to the 38th parallel.

On June 27, 1950, it adopted Resolution 83, recommending that members of the United Nations provide assistance to the Republic of Korea "to repel the armed attack and to restore international peace and security to the area".

The first non-Korean and non-US unit to see combat was No. 77 Squadron, Royal Australian Air Force, which began escort, patrol and ground attack sorties from Iwakuni, Japan on 2 July 1950.

Security Council Resolution 84, adopted on July 7, 1950, recommended that members providing military forces and other assistance to South Korea "make such forces and other assistance available to a unified command under the United States of America".

President Syngman Rhee of the Republic of Korea assigned operational command of ROK ground, sea, and air forces to General MacArthur as Commander-in-Chief UN Command (CINCUNC) in a letter (the "Pusan Letter") of July 15, 1950:

In view of the common military effort of the United Nations on behalf of the Republic of Korea, in which all military forces, land, sea and air, of all the United Nations fighting in or near Korea have been placed under your operational command, and in which you have been designated Supreme Commander United Nations Forces, I am happy to assign to you command authority over all land, sea, and air forces of the Republic of Korea during the period of the continuation of the present state of hostilities, such command to be exercised either by you personally or by such military commander or commanders to whom you may delegate the exercise of this authority within Korea or in adjacent seas.

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