Iraq formally declared the end of the US-led coalition’s military mission against Islamic State on September 30, as the last coalition troops and equipment left Erbil Air Base.

Prime Minister Ali Faleh al-Zaidi told an official ceremony marking the end of the mission that the country had entered a new phase in which it takes full responsibility for its own security. The government has named October 1 Sovereignty Day.

“The end of the international coalition’s mission does not mean the end of our battle against terrorism, but rather Iraq’s transition to a stage in which it assumes full responsibility for its security and stability,” he said.

Washington and its partners had “formally concluded Operation Inherent Resolve in Iraq”, Chief Pentagon Spokesman Sean Parnell said in a statement, adding that the departure of coalition forces and equipment from Erbil air base marked the end of the military mission. The US will continue to provide targeted training and intelligence support to Iraqi forces.

“Our mission is accomplished and the final withdrawal from Erbil has been completed,” the coalition said, adding that relations between its armies would “move into another phase of cooperation.”

The handover closes a 12-year campaign launched in August 2014, after Islamic State overran large parts of Iraq and Syria. It also leaves Baghdad to face the Iran-aligned armed factions without foreign troops on Iraqi soil. Several of those groups had made a complete US withdrawal a condition for placing their weapons under state control, and the issue has grown more urgent amid renewed US-Iran military escalation.

Michael Knights, an adjunct fellow at the Washington Institute, was more cautious. “The Iranians are maintaining interest in Iraq, and the US is losing interest. Whenever that happens, it’s not a good outcome, typically,” he told the paper.

The drawdown followed a September 2024 agreement between Baghdad and Washington. The last coalition advisers left Ain al-Asad air base and the Joint Operations Command in January, leaving a contingent in Erbil to support operations against Islamic State in Syria. About 2,000 Americans were in Iraq as of February, CBS News reported.

US personnel and air-defence systems stayed in the Kurdistan Region for the final phase, where coalition forces shot down 10 explosive-laden drones over Erbil in early September. Troops and equipment then left the region daily through the second half of the month.

Al-Zaidi said transferring joint operations to the office of the commander-in-chief gave the state an institutional framework for managing security, and that future cooperation with coalition members would include the use of digital technologies.

“Security cooperation will remain an open path with friends from the international coalition and will be more effective and focused,” he said, before thanking the coalition countries, commanders, officers, trainers and advisers who had worked alongside Iraqi forces.

“The mission has ended with victory, and the responsibility of protecting this victory rests with all of us today,” he added.

Baghdad is separately pursuing a plan to bring weapons under state control. Al-Zaidi announced on September 21 a phased process opening with a 90-day de-escalation period, with disarmament to be completed by June 30, 2027, well after the September 30 deadline Iraq’s main political forces had originally set. The country’s four top officials were due to meet on September 28 to discuss the factions’ weapons.

Kataeb Hezbollah, one of the hardline groups that has refused to disarm while foreign troops remained, welcomed the withdrawal but warned that “a government that doesn’t work for the good of its people will be brought down by all possible means”.

“No weapons outside the umbrella of the law, and no force outside state institutions, in accordance with the constitution, the guidance of our religious authority and what our people want,” al-Zaidi said.