Iranians and the Karbala Attack

Bill Roggio says the attack which resulted in the deaths of 5 American soldiers was a little too sophisticated:

The American Forces Information Service provides the details of the attack in Karbala. Based on the sophisticated nature of the raid, as well as the response, or cryptic non-responses, from multiple military and intelligence sources, this raid appears to have been directed and executed by the Qods Force branch of the Iranian Republican Guard Corps. My sources agreed this is far to sophisticated an operation for the Mahdi Army or Badr Corps, while al-Qaeda in Iraq would have a difficult time mounting such an operation in the Shia south. "The Karbala Government Center raid the other day was a little too professional for JAM [Jaish al-Mahdi, or the Mahdi Army]," according to a military source.

The Iranian seem to be saying, "bomb us please!"