American troops have started to draw down from Iraq following Baghdad's declaration of victory over Islamic State (IS) last year, according to officials.
In Baghdad, an Iraqi government spokesman confirmed that the drawdown has begun, though he stressed it is still in its early stages and does not mark the beginning of a complete pullout of US forces.
Dozens of American soldiers have been transported from Iraq to Afghanistan on daily flights over the past week, along with weapons and equipment, western contractors based in Iraq said.
Reporters at the Al-Asad base in western Iraq said they witnessed troop movements reflecting the contractors' account.
Coalition spokesman Col Ryan Dillon said: "Continued coalition presence in Iraq will be conditions-based, proportional to the need and in coordination with the government of Iraq."
Iraqi government spokesman Saad al-Hadithi said: "The battle against Daesh (IS) has ended, and so the level of the American presence will be reduced."
Mr al-Hadithi spoke just hours after reports of the American drawdown - the first since the war against IS was launched more than three years ago.
One senior Iraqi official close to Prime Minister Haider al-Abadi said 60% of all American troops currently in country will be withdrawn, according to the initial agreement reached with the US.
The plan would leave a force of about 4,000 US troops to continue training the Iraqi military.
A Pentagon report released in November said there were 8,892 US troops in Iraq as of late September.
America first launched air strikes against IS in Iraq in August 2014. At the time the military intervention was described as "limited", but as Iraq's military struggled to roll back the extremists, the US-led coalition's footprint in the country steadily grew.
The drawdown of US forces comes just three months ahead of national elections in Iraq, where the indefinite presence of American troops continues to be a divisive issue.
Mr al-Abadi, who is looking to remain in office for another term, has long struggled to balance the often competing interests of Iraq's two key allies: Iran and the United States.
While the US has closely backed key Iraqi military victories over IS such as the retaking of the city of Mosul, Iraq's Shia-led paramilitary forces with close ties to Iran have called for the withdrawal of US forces. The prime minister has previously stated that Iraq's military will need American training for years to come.
The Iraq drawdown also follows the release of the Pentagon's National Defence Strategy, which cited China's rapidly expanding military and an increasingly aggressive Russia as the US military's top national security priorities.