As tensions with Iran remain high, the Pentagon and NATO have paused the training of Iraqi police and military units over concerns of insider attacks.

Military officials are concerned that fighters from the Popular Mobilization Units (PMUs), Shia militant groups and Iranian proxies, might have infiltrated the ranks of the Iraqi police and military. (Historically, green-on-blue attacks have been more common in Afghanistan.)

These concerns are fairly well-grounded. Shia Muslims are a majority in Iraq and they control much of the government, which, in turn, is under the influence of Tehran. Numerous American and NATO units in the country are housed or work on the same bases as the Iraqis.