Quote Originally Posted by Hosakawa Tito
Iran accused of supplying Iraqi Shias Militants

Here's the article on the same story in my local paper.

Lets not forget the other countries involved in supplying both sides with weapons in that one, shall we.
I suspect, if you look at sheer volume of resources, the US might be one of the largest contributors to the insurgency. IIRC 12 billion dollars are unaccounted for in the last few years, and how much of that has been skimmed off by insurgency sympathisers? Given most of the violence has come from the Sunnis whom the Iranians hate, embezzled American money may well have killed more American soldiers in total than Iranian money.