Government spokesman Saad al-Hadithi says "the battle against Daesh has ended and so the level of the American presence will be reduced".
If the drawdown is true, it represents the first of its kind since the war against Islamic State (IS, formerly ISIS) was launched over three years ago. Some foreign journalist confirmed the troops movement at Ain Asad base.
Last week, U.S. military spokesman Col. Ryan Dillon told CBN News in a satellite Pentagon briefing that the US-led military coalition's presence in Iraq "will be conditions-based, proportional to the need" and determined "in coordination with the government of Iraq". The Associated Press are also reporting that eventually 60 per cent of American troops in the country would be withdrawn.
Al-Hadithi stressed the drawdown is still in its early stages and at present does not mark the beginning of a complete withdrawal of US forces.
US military personnel records made public last fall indicated that there may have been as many as 9,000 American troops in Iraq assisting with the advise-and-assist mission with the Iraqi military.
Daesh has been driven out by the Iraqi army, backed by a US -led coalition, from territory overran by the terrorist group in northern and western Iraq in 2014.
Is the USA drawing down its military presence in Iraq, following a declaration of victory over ISIS?
Two major Iraqi Shi'ite groups backed by Iran are demanding all US forces leave Iraq, opposing plans by Baghdad and Washington to keep some there for training and advisory purposes.
While the USA has closely backed key Iraqi military victories over IS such as the retaking of the city of Mosul, 's Shiite-led paramilitary forces with close ties to Iran have called for the withdrawal of US forces. The Mobilization force established after Ayatollah Siestani's appeal to the masses and Iranian advisors played important role in the struggle.
Earlier this week, the US-led coalition issued a press release, which outlined its shift from combat operations in Iraq to sustaining and securing the advances achieved in their fight against Daesh. In 2014, at the height of the Sunni militant group's power, IS controlled almost a third of Iraqi territory.
There were some 170,000 American troops in Iraq in the aftermath of fall of Saddam Hussein regime in 2003.
Hashemi added that part of the United States troops would be sent to Afghanistan.
Iraqi security forces have arrested Islamic State's top oil chief while he was trying to cross the border into Syria, Tehran-based Fars News Agency reported on Friday, quoting military sources.