In the battle against the Islamic State (IS), it seems clear that some forces rallying under the umbrella of Iraq's Popular Mobilization Units have direct ideological and organizational links to the Iranians. The affiliation to a foreign country raises a red flag as to what role and influence these forces eventually could hold.

These foreign-linked forces are mostly former militias that were founded through direct Iranian support, either during the Iran-Iraq War or after 2003, as Iran attempted to support the Iraqi resistance against the United States. Most notably among these groups are the Badr Organization, Asa’ib Ahl al-Haq, the Hezbollah Brigades and Saraya al-Khorasani.

In March — amid the battle with IS for Tikrit and after the US-led coalition conducted strikes against IS — a number of militias that had joined the Popular Mobilization Units suspended their participation in the fighting in protest against what they described as “the US intervention."

Hadi al-Amiri, leader of the Iraqi political party Badr Organization, headed a meeting that month in which the militias threatened, “The militias will not break into Tikrit and will leave the task [of liberating Tikrit] to the police and army without cooperating with them, if the coalition and the government insist on this [US] participation.”