US forces withdraw from their remaining bases in Iraq on September 30, 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 ↧ US forces exit Iraq, emboldening Iran's proxies and Islamic State 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.