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Citing the inability of the Joint Commission to make progress, the U.S. government decided to hold an election under United Nations auspices with the aim of creating an independent Korea. The Soviet authorities and the Korean Communists refused to co-operate on the grounds it would not be fair, and many South Korean politicians also boycotted it. A general election was held in the South on 10 May 1948. It was marred by terrorism and sabotage resulting in 600 deaths. North Korea held parliamentary elections three months later on 25 August.

Why did the Korean Communists and the Soviets refuse to cooperate in the elections and creation of independent Korea?
it would not be fair