BAGHDAD — The U.S.-led coalition concluded its mission in Iraq on Wednesday with the final withdrawal of troops from the autonomous Kurdistan region, ending more than a decade of military presence aimed at countering the Islamic State group across Iraq and Syria.

Coalition forces first deployed to Iraq and Syria in 2014 after the Islamic State seized significant territory and committed widespread atrocities. The group was defeated in Iraq in 2017 and in Syria in 2019, but coalition forces remained to battle remnants of the organization.

Baghdad and Washington reached an agreement in 2024 to wind down the coalition's mission, leading to a gradual withdrawal from bases throughout Iraq until forces were restricted to the Kurdistan region.

Iraqi Prime Minister Ali al-Zaidi declared Oct. 1 Sovereignty Day, marking Iraq's completion of its path toward full sovereignty. Heads of Iraq's executive, legislative and judicial branches affirmed Monday that the date represents a "national occasion that affirms the completion of Iraq's path toward sovereignty and consolidates the presence of the state and its institutions."

The Iraqi government views the coalition's withdrawal as eliminating a key justification that Tehran-backed militant factions have used to retain weapons outside state control—an issue that has fueled internal tensions.

Zaidi, who assumed power this year with U.S. backing, has pledged to enforce the state's monopoly on arms and ensure all armed factions surrender their weapons to state authority. His government initially set Sept. 30 as a deadline for disarmament but later rescinded it as discussions continued regarding weapons regulation, which officials acknowledge will require a longer resolution period.

Several powerful groups have refused to disarm. Senior Iraqi politicians have since intervened to broker a compromise deal.

These factions have outlined conditions for disarmament, demanding not only the withdrawal of foreign troops but also an end to American political and economic interference in Iraq.

Kataeb Hezbollah, one of the most powerful groups, said Monday that the "withdrawal of the occupation forces is a start towards achieving full sovereignty." The group also warned that "a government that doesn't work for the good of its people will be brought down by all possible means."

During the fight against the Islamic State, the U.S.-led coalition and Tehran-backed factions fought the jihadists as a common enemy. After the group's defeat, the continued presence of coalition forces became a persistent source of friction. The factions repeatedly demanded U.S. troop withdrawal and launched attacks using drones and missiles, prompting American retaliatory strikes that killed several faction commanders over the years.