Army spokesman Colonel Tom Collins said Gen McChrystal notified the service of his plans, but he has not yet submitted formal retirement papers. It is not clear when he would leave the service, but the process usually takes a few months.
US president Barack Obama has praised Gen McChrystal's long Army career but said his intemperate remarks in a magazine article that appeared last week were too much.
Gen McChrystal apologized for the remarks in Rolling Stone magazine and flew to Washington last week to resign as commanding general of the war.
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