The U.S. military will end its current mission in Iraq against the militant organization ISIS by the end of 2026 and transition to a new phase that likely will involve a significant withdrawal of American forces in the country, according to senior U.S. officials.
But Washington will maintain a military footprint in the country to continue the fight against global terrorism, they added, declining to offer specifics about expected troop levels or how the transition would work. There are presently about 2,500 American troops in Iraq.
The move will occur in two phases, with the U.S. counterterrorism mission in Iraq, Operation Inherent Resolve, wrapping up in September 2025 but continuing in a transitionary form until at least September 2026, when it is expected to formally end.
A senior Biden administration official said the details will be worked out over time but to expect some change in the U.S. footprint.
“As we go through this transition into a bilateral relationship, there could very well be changes in the numbers, changes in the activities that we do [to] align ourselves better with the bilateral interests that we have,” the official said. “A lot of that is going to be an ongoing discussion.”
The U.S. sent forces into Iraq in 2014 at the invitation of the Iraqi government, which was struggling at the time to counter the growing threat of ISIS that had captured vast swaths of Iraq and northeast Syria. The U.S. has always been subject to Baghdad’s invitation and a withdrawal if the government demanded it.
Iraqi officials announced publicly earlier this month that the U.S. would withdraw its troops in two phases, starting now and continuing into 2025, with the last phase ending in 2026. A small force is expected to remain in Iraq’s Kurdistan region.
But the senior administration official did not characterize the changing relationship as a withdrawal, stressing there will be a continued security partnership.
“I’d like to emphasize that this is an evolution of the military mission in Iraq,” the official said. “We are moving towards the type of productive, long-term security relationship the United States has with partners around the world.”
Iraqi Prime Minister Mohammed Shia al-Sudani, who has ties to Iran, has called for the U.S. to transition its counter-ISIS mission, recently increasing those calls after American forces have fought against Iranian-backed militia groups in Iraq during the ongoing war in Gaza.
Al-Sudani has been criticized for being too close to the Popular Mobilization Forces, an umbrella group of Iraqi security forces, many of which are backed by Iran.
But the Iraqi leader has faulted both sides for trading fire on his territory, which he considers a violation of his nation’s territory, and has also called for a more enduring partnership with the U.S. focused on economic and other cooperation.
Al-Sudani visited the U.S. in a high-profile trip in April and met with President Biden, where they discussed the transition to a new phase. His trip came after the start of talks about a transition in January.
The U.S. has expressed confidence that Iraq can defend its territory against ISIS and other extremist groups that threaten the country, and officials said they will continue to support Iraqi security forces in the new phase.
A senior defense official said the mission was “always to support and not replace the Iraqi security forces.”
“Today, the coalition’s local security partners are better able to ensure that ISIS can never again cause havoc in the region,” the official said, explaining the U.S. has trained and equipped more than 225,000 Iraqis and given them $4 billion in military aid.
“Through the advise and assist mission, the coalition, during these past years, we’ve seen very significant improvement in the Iraqi Security Forces capability,” the official added.
ISIS has lost most of its territory since it swept Iraq and Syria in 2014, but it has rebounded in the past few years since the 2021 U.S. withdrawal from Afghanistan. This year alone, ISIS-K, the branch in Afghanistan, has been responsible for deadly attacks in Russia and Iran that killed more than a hundred people combined.
If the U.S. withdraws all of its forces, that could leave a power vacuum vulnerable to being filled by Iran, which already has vast influence over Iraq.
It could also push the U.S. to withdraw its about 900 troops remaining in Syria, given they would be isolated from any support in Iraq. But if there is a remaining force in the Kurdistan region, the U.S. may be able to support its forces in Syria.
The senior defense official said the U.S. was transitioning its structure in Iraq “because the mission environment has changed.”
“We talked about the vast territorial sweep of ISIS and the large population that lived under its brutal rule. ISIS no longer controls that kind of territory,” the official said. “It no longer has a population under its command. It has fighters, it has cells. It has a presence, and that needs continued effort to ensure its enduring defeat.
“But that mission, that evolution of the threat,” the official said, “means it’s time to evolve this mission.”