The former US commander in Afghanistan, General Stanley McChrystal, who was fired last week by President Barack Obama, is to leave the US Army.
He was dismissed after criticising US administration officials in a Rolling Stone magazine profile.
US Army spokesman Col Tom Collins told AP that Gen McChrystal had notified the service that he wanted to retire but had yet to submit formal plans.
Mr Obama has nominated Gen David Petraeus to replace the sacked general.
Gen McChrystal, a four-star general, and his aides were quoted in the magazine article as making disparaging remarks about Mr Obama and other senior colleagues.
It is still unclear when he will officially leave the service as the process typically takes several months.
Gen Petraeus, who led the troop "surge" in Iraq, was nominated by President Obama last week to replace Gen McChrystal.
He will appear on Tuesday before a key US Senate panel in a hearing on his confirmation to lead the Afghan war.