The U.S. plans to reduce troop levels in Iraq to 3,500 from about 5,200, a U.S. official confirmed to ABC News.
The reduction in forces had been anticipated, with U.S. military officials highlighting the Iraqi military's growing ability to carry out independent operations against the remnants of ISIS.
Although officially at about 5,200 since late 2016, when U.S. training efforts to battle ISIS peaked, that figure actually was a bit higher because of troop rotations and other factors.
The process for the drawdown has already begun, but the U.S. official did not elaborate on how long it would take to complete.
A spokesman for U.S. Central Command declined to comment, but cited the progress made by Iraq's military.
The Wall Street Journal was first to report the reduction of forces in Iraq.
The United States and Iraq began discussions earlier this year about the future of the U.S. troops in Iraq.
In June, following a meeting with Iraqi Prime Minister Mustafa Al-Kadhimi in Baghdad, Gen. Kenneth McKenzie told ABC News it appeared Iraq wanted to keep a U.S., NATO and coalition presence there long term.
McKenzie has said several times this summer it was possible the U.S. troop presence in Iraq could be reduced as the Iraqi military continued making progress. But he also said the size of any troop reduction would be a decision made by the White House.
"We were there, and now we’re getting out," he told reporters. "We’ll be leaving shortly. "
Trump ordered a total U.S. troop withdrawal from Syria last fall during Turkey's invasion into northern Syria, but he was convinced to keep troops in eastern Syria to protect Kurdish oil fields from ISIS. About 500 U.S. troops remain, in a southern outpost close to the border with Jordan.