It was not immediately clear if all roughly 5,000 U.S. troops would leave Iraq.
Several helicopters could be heard flying over Baghdad on Monday night. It was not immediately clear if this was a related development. The letter said coalition forces would be using helicopters to evacuate.
“In deference to the sovereignty of the Republic of Iraq, and as requested by the Iraqi Parliament and the Prime Minister, the coalition will be repositioning forces over the course of the coming days and weeks to prepare for onward movement,” read the letter.
It was signed by the United States Marine Corps Brigadier General William H. Seely III, commanding general of Task Force Iraq, the U.S.-led military coalition against Islamic State
The authenticity of the letter, which was addressed to the Iraqi defense ministry’s Combined Joint Operations Baghdad, was confirmed to Reuters independently by an Iraqi military source.
“We respect your sovereign decision to order our departure,” it said.