A US congresswoman has called for an investigation into claims that Iraq war veterans were threatened with being sent to Iraq unless they stayed on.
Troops based in Colorado have already spent a year in Iraq
Diana DeGette said she had been contacted by soldiers based at Fort Carson, near Colorado Springs.
She has asked Congress to look into whether coercion was exerted to make sure the voluntary US army had enough troops for the "war on terror".
Fort Carson denies this and says it is exceeding re-enlistment targets.
According to local media reports, soldiers from the 3rd Brigade Combat Team nearing the end of their duty were told they faced re-assignment to units expected to be deployed to Iraq or South Korea unless they re-enlisted at the end of the month or extended their duty until the end of 2007.
Those who re-enlisted or extended their stay would stay with the brigade, which has already spent a year in Iraq.
"There are legitimate questions as to whether officials at the White House or civilian leadership at the Pentagon is pressuring army officers at Fort Carson and other military installations to coerce Iraq war veterans to re-enlist in order to maintain the force levels necessary to fight the war in Iraq and war on terror," Ms DeGette told the Denver Post newspaper.
"If this is that case, as I've been hearing, it is completely unacceptable," she added.
Fort Carson spokesman Lt Justin Journeay told the Denver Post that soldiers were recently given a form, giving them the option to re-enlist, extend their enlistment, or do neither, with the understanding they could be reassigned.
Fort Carson was exceeding re-enlistment targets, he added.