Moscow Conference of Foreign Ministers
The foreign ministers of the US, Britain and the Soviet Union agreed in Moscow to set up a provisional democratic government for Korea under a trusteeship of up to five years.

Army Information Branch · Public domain · Source
In December 1945 the foreign ministers of the US, Britain and the Soviet Union met in Moscow to settle post-war questions. On Korea they decided (1) to establish a provisional democratic government, (2) to set up a US–Soviet Joint Commission to assist it, and (3) to place Korea under a four-power trusteeship (US, Britain, China, USSR) for up to five years.
When the decision became known, trusteeship split left and right sharply in Korea.