A interesting observation by Juan Cole:

Note too that the Sunni Arab neighborhoods have the explosively formed projectiles, just as do the Shiite neighborhoods. Iran is not giving them to Sunnis, and certainly not to 'al-Qaeda-allied' Sunnis. Ipso facto, Iran cannot be the only source of EFPs, and it is not established except by allegation and innuendo that they are a source at all. (If the Sunni Arab guerrillas can make EFPs, so could Iraqi Shiites).

The Maliki government is trying to buy arms from the Mafia as well, as Cole demonstrates in the same post. All for national unity, of course.