US Army chief, General Ray Odierno, warned against creating the impression of an American "occupation" of Iraq by leaving too many troops in the country after a year-end deadline to withdraw.
Odierno told reporters the United States had to carefully balance how many troops were needed to assist Iraqi forces while scaling back the American profile in a country where anti-US sentiment still runs high.
"I will say when I was leaving Iraq a year ago, I always felt we had to be careful about leaving too many people in Iraq," said Odierno, who took over as Army chief of staff on Wednesday.
"The larger the force that we leave behind ...(the more) comments of 'occupation force' remain. And we get away from why we are really there -- to help them to continue to develop," he added.
Odierno commanded US forces in Iraq until last year and was one of the senior officers who spearheaded the troop "surge" in 2007, which the military believes turned the tide in the war and reduced sectarian violence.
He spoke amid a debate in Washington over the scale of a possible future US military mission in Iraq and after Defense Secretary Leon Panetta endorsed a tentative plan for a force of 3,000-4,000 troops.
Some US lawmakers have criticized that number of soldiers and say senior officers favor a larger force of at least 10,000, which would include a unit deployed in northern Iraq to defuse Arab-Kurdish tensions.
Odierno's intervention carries weight given his battlefield experience in Iraq -- he spent a total of 56 months there -- and his reputation previously for cautioning against dramatic reductions in the American troop presence.
He said that the final decision about the size of a post-2011 US force would be up to Iraq's government, American leaders and military commanders.
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"I'm not saying 3-5,000 is the right number," said Odierno, but "there comes a time...when it (US presence) becomes counter-productive."
"I’m not quite sure what the right number is, but there’s a number there somewhere that is -- you’ve got be careful about," he added.
As commander in Iraq, Odierno -- whose son was badly wounded in the war -- successfully lobbied President Barack Obama to slow the pace of a planned withdrawal.
The current security agreement between Washington and Baghdad calls for all American troops to pull out by the end of the year. Any future US military role in the country depends on negotiations under way with the Iraqi government.
Odierno has warned that territorial disputes between Kurdish and Iraqi government forces in the north pose the greatest threat to Iraq's stability and credited the US presence with helping to calm tensions.
But he said Thursday that it was possible that a 5,000-strong US force in the north, in which he played a pivotal role in bringing into force, would no longer be necessary amid recent progress.
"I've heard some discussion, 'well we need 5,000 people to work the Arab-Kurd issue,'" he said. "I've read some things lately that we think they're starting to handle that. There's been some progress made and the forces that we've developed, they feel can handle that for example.
"If that's the case, then we don't need those 5,000 (troops in the north)."
US officials are looking at shifting some tasks currently performed by American troops in Iraq to private contractors.
About 46,000 US forces remain in Iraq in a mainly advisory role, though the Americans used attack helicopters to strike at Iranian-backed militia in recent months.
Odierno also predicted that there would "probably" be a US military base in Iraq in the future, although it would be located "outside of Baghdad."