"There is a coordination with the Iraqi government and the United States to gradually reduce the number of the USA troops in Iraq as victory has been achieved over IS group", spokesman Saad al-Hadithi told Xinhua via phone.
"Enabled by accelerated successes following the liberation of Mosul, the Coalition will shift its focus in Iraq from enabling combat operations to sustaining military gains against Daesh".
A senior Iraqi official close to Prime Minister Haider al-Abadi said 60 percent of all USA troops now in the country will be withdrawn, citing an agreement reached between Baghdad and Washington.
One example of how the U.S. mission in Iraq is already transitioning is the changing role of how the U.S. Air Force is helping the Iraqi military.
According to western contractors at a US-led coalition base in Iraq, American soldiers have been transported from Iraq to Afghanistan on daily flights over the past week, along with weapons and equipment. Gen. Jonathan Braga, the coalition's director of operations, referring to the Arabic acronym for ISIS.
Last October, the Iraqi government took unilateral control of Kirkuk in response to a referendum conducted by the Kurdistan Region on Sep.
Islamic State is regrouping in Syria despite being driven from its strongholds as the jihadi force exploits rivalries between its foes in an attempt to stage a comeback, Syrian opposition and regime fighters say.
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.
According to the Western contractors, the drawdown began last week and a number of USA troops have left bases on daily flights. At their peak, USA troop levels in Iraq stood near 166,000.
Two months later, Iraq's army and USA -led coalition allies launched the offensive to free Mosul from ISIS.
"We are serious about getting the Americans out, using the force of arms because the Americans don't understand any other language", its spokesman, Jaafar al-Husseini, told Beirut-based al-Mayadeen TV on Monday evening.
The coalition estimates that ISIS has lost 98 percent of the territory in Iraq and Syria it once controlled as part of its self-declared caliphate.
There were some 170,000 American troops in Iraq in 2007 at the height of the surge of USA forces to combat sectarian violence unleashed by the US -led invasion of the country to oust dictator Saddam Hussein.
Despite that information, the US military cites the official number of USA troops in Iraq as approximately 5,262.