"If the political process continues to go positively and if the development of the security forces continues to go on, I do believe that we will be able to make fairly substantial reductions after these elections, in the spring," said General George Casey on Wednesday.
He was speaking after talks with visiting US Defence Secretary Donald Rumsfeld, US ambassador Zalmay Khalilzad and other commanders.
"From now until the elections we hope to have transferred 10 major cities," Muwaffaq al-Rubai, the chairman of a new transition task force said.
General elections are scheduled for 15 December.
The handing over of security to newly-formed Iraqi forces was expected to be one of the main topics raised during Rumsfeld's surprise visit, said al-Rubai.
A joint US-Iraqi transition committee is to report to Prime Minister Ibrahim al-Jaafari on transferring security from US-led troops to Iraqi forces within 60 days, with a final report expected a month later, al-Rubai said.
George Bush has refused to set a
timetable for US troop withdrawal
Transfer of responsibilities will depend on how fast Iraqi forces are able to meet a set of five or six criteria, still to be defined, allowing them to operate alone against fighters, al-Rubai added.
Meeting the criteria, which will include better coordination between police and army, will allow for "the transfer of some secured areas from the multinational forces" starting with a number of cities, he said.
US forces might also hand over control of parts of Baghdad, he added.
Khalilzad has said that the task force "will establish no timeline" but will "identify conditions sanctioned by the leadership of the Iraqi government and the multinational coalition".
The setting up of the transition task force comes at a time when US forces are seeking to speed up the training of Iraqi forces to allow them to take responsibility for stabilising the war-torn country.
US President George Bush has refused to set a timetable for the withdrawal of the 138,000 US soldiers in Iraq, but has said American forces will stand down as Iraqi forces gradually take over.
The rising US toll in Iraq is eroding
public support for the war
Rumsfeld's visit comes at a time when the Pentagon has expressed concern over the readiness of Iraqi security forces to take over.
Pentagon officials have refused to comment on the specifics, but have acknowledged that only a small number of the 171,500 Iraqi soldiers and police are ready to mount independent operations against fighters.
Maintaining a high-level of troops in Iraq has put severe strains on the US military, and the rising US toll which has reached 1781 is eroding US public support for the war.
A majority of Americans now believe the United States will not win the war, nor establish a democratic government in Iraq, according to a USA Today/CNN/Gallup poll published on Wednesday.
Thirty-two percent believe outright that the US cannot win the war in Iraq, 21% believe the war could be won but in the end will not be won, while 43% predict a victory.
And by a 58% to 37% margin, Americans said their government would not be able to establish a democratic government in Iraq.