The US Defence Department said it was replacing the US generals in charge of Iraq and crucial Central Command, in the latest step of a shake-up of senior US diplomatic and military personnel.
Defence Secretary Robert Gates said he would recommend that General George Casey, commander of multinational forces in Iraq, be replaced by Lieutenant General David Petraeus.
He also proposed Admiral William Fallon to succeed General John Abizaid as commander of Central Command, overseeing US forces from North Africa to Central Asia.
Petraeus, 54, currently serves as the commander of the US Army Combined Arms Center at Fort Leavenworth, Kansas.
From June 2004 to September 2005 he was in charge of training the new Iraqi Army and security forces, an initiative which Bush has identified as a priority if the United States is going to reduce its troop strength in Iraq.
Petraeus commanded the 101st Airborne Division during the 2003 invasion of Iraq and was widely praised for his subsequent work administering the northern city of Mosul.
"General Petraeus is an expert in irregular warfare and stability operations (and)... Has been leading the effort to rewrite the military's doctrine for defeating an insurgency," the defence secretary added.
"He'll bring all the tools to enable Iraqi and coalition forces to create a stable and securee Iraq," Gates said in a statement.
Casey, 58, would become Army chief of staff, he said.
Fallon, 62, nominated to head Central Command, was a navy combat pilot during the Vietnam War, commanded an attack squadron during the first Gulf War in 1991 and was involved in NATO's Operation Deliberate Force in Bosnia.