General Stanley McChrystal, who was fired last week as the top U.S. and NATO commander in Afghanistan, plans to retire, an army spokesman said Monday.

The U.S. and NATO commander in Afghanistan U.S. General Stanley McChrystal wears earplugs as he leaves by helicopter after a meeting between Afghan President Hamid Karzai and tribal leaders in Kandahar city June 13, 2010. [Xinhua]

McChrystal, 55, notified the service of his plans, but has not yet submitted formal retirement papers, according to Army spokesman Col. Tom Collins.

It remained unclear how much more time he had in uniform, Collins added.

McChrystal was forced to step down after he and his aides enraged the White House by disparaging the president and other top civilian advisers, in an article for the Rolling Stone magazine.

President Barack Obama praised McChrystal's long Army career while announcing his ouster on Wednesday, but said his intemperate remarks in a magazine article that appeared last week could not be abided.

Obama has picked General David Petraeus to replace McChrystal as the top U.S. and NATO general in Kabul.

A Senate hearing on Petraeus's nomination is scheduled for Tuesday.