Abizaid, who became chief of US Central Command in July 2003, just months after US troops invaded Iraq, has served at the post longer than any of his predecessors, agreeing earlier this year to a request by then defence secretary Donald Rumsfeld to remain on the job.

"In the spring of 2006, secretary Rumsfeld asked General Abizaid to remain as the commander of US Central Command until early in 2007," the spokesman said. "He does not intend to extend beyond that period."

Abizaid played a role in designing the March 2003 US-led invasion of Iraq to topple Saddam Hussein's regime. Abizaid earlier this year warned that Iraq was slipping toward civil war as sectarian violence increased.

The announcement of Abizaid's departure comes as US President George W Bush is conducting a review of his policy in Iraq, which has failed to halt the deteriorating security environment in the country.

Bush replaced Rumsfeld with Robert Gates, who took over as defence secretary on Monday and arrived in Iraq on Wednesday for a briefing from US military commanders.

Sound Off...What do you think? Join the discussion.

Copyright 2009 Deutsche Presse-Agentur. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

More Military Headlines

• Pentagon Seeks More Power From Vehicles
• Underway at Last!
• Torn Between Two Loves
• Iraqis Taking the Lead? Yes and No
• Cool Under Fire