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In page Cheka:

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It is believed that there were more than three million deserters from the Red Army in 1919 and 1920[citation needed]. Approximately 500,000 deserters were arrested in 1919 and close to 800,000 in 1920, by troops of the 'Special Punitive Department' of the Cheka, created to punish desertions.[1][2] These troops were used to forcibly repatriate deserters, taking and shooting hostages to force compliance or to set an example.