BAGHDAD, Sept 30 (Reuters): US forces withdraw from their remaining bases in Iraq on Wednesday, raising fears they will leave behind a security vacuum, further embolden Iranian-backed militias and give the resurgent Islamic State group an opening to regroup.

The departure, ‌celebrated as a victory by Tehran and its allies, was agreed in 2024 under President Joe Biden and carried out by Donald Trump's administration even as it wages war against Iran, which wields influence in Iraq through proxies.

It comes 23 years after US-led forces toppled dictator Saddam Hussein, then triggered upheaval and chaos, culminating with the rise of Islamic State.

While the departure of US forces is broadly popular among Iraqis, some worry that security forces trained and funded by the United States still can't protect the country, where 4,500 American forces died in ⁠more than 20 years of war.

"The lesson from the past two decades is that security vacuums can be extremely dangerous," said Jassim al-Bahadli, an Iraqi analyst who advises the security forces.

US forces invaded Iraq in 2003 and went on to occupy the country, install a Shi'ite-led government and fight a years-long counterinsurgency — first by Saddam loyalists, then al-Qaeda — before withdrawing at the end of 2011. They returned less than three years later to help Iraqi forces defeat the Sunni militant group Islamic State in a major war from 2014 to 2017.

Around twice as many Americans died in "Operation Iraqi Freedom" as in the parallel war in Afghanistan, which ended with an abrupt US withdrawal in 2021.

In this year's conflict with Iran, 7 of the 18 US service members listed as killed were in Iraq, the last an army sergeant who died during the controlled detonation of a drone at a base ‌near Erbil ⁠in July.

Photo from Reuters