The United States military has formally completed its withdrawal of troops from Iraq, the Pentagon announced Wednesday, closing a chapter of American military engagement that spanned more than two decades. The departure concludes a mission that began with the 2003 invasion and later evolved into a counter-Islamic State campaign that drew thousands of troops back into the country after 2014.

Pentagon officials confirmed that all remaining U.S. forces assigned to the counter-ISIS mission have departed Iraqi soil, fulfilling a timeline that had been negotiated between Washington and Baghdad. The two governments had been in talks for years over the future of the U.S. military presence, with Iraq's government facing domestic political pressure to assert full sovereignty over its territory.

The withdrawal represents the culmination of a long transition process in which Iraqi security forces assumed primary responsibility for operations against remnants of the Islamic State. U.S. officials have stated that while ISIS has been significantly degraded, the group continues to pose a residual threat in parts of Iraq and Syria.

The formal end of the military mission does not necessarily sever all U.S.-Iraq security ties. Officials have indicated that other forms of cooperation, including training, advising, and intelligence sharing, may continue under separate arrangements. The State Department is expected to play a larger role going forward in managing the bilateral relationship.

The withdrawal closes a period marked by shifting U.S. policy, multiple presidential administrations, and evolving military objectives in the region. American troop levels in Iraq had fluctuated significantly over the years, from a peak of roughly 170,000 during the 2007 surge to a near-complete pullout in 2011, followed by a return of forces after ISIS seized large swaths of Iraqi territory in 2014.