The raid on the dangerous Shiite slum was aimed at capturing an alleged rogue militia chief, one of thousands of fighters who have broken with Muqtada al-Sadr's mainstream Mahdi Army.
The Shiite cleric has ordered gunmen loyal to him to put down their arms. But thousands of followers dissatisfied with being taken out of the fight have formed a loose confederation armed and trained by Iran.
The claim is unsupported by any evidence. There is not even a cite of an anonymous source. Since no source is mentioned, the Washington Post has made the assertion in its own voice as a definite fact.
The claim is very strong. Proof that Iran is aiding the Mahdi army would not prove the claim, since it specifically claims that Iran is aiding ex Mahdi army fighters who have broken with al Sadr. I think that it would be crazy for Iran to do this, which doesn't mean that they aren't.
Later un-named sources make a different claim
In the Sadr City raid, the U.S. military said forces killed "an estimated 49 criminals" in three linked attacks during an intelligence-driven raid to capture the rogue Shiite kidnapper who was partially funded by Iran. The man was not named.
This is bizarre to say the least. Kidnapping is highly profitable, highly risky and universally detested. Why would a kidnapper be funded ? Sold arms maybe. His thugs trained maybe. But financed ? Why would Iran finance someone who obtains lots of money using dispicable means. The money would not be needed to make trouble in Iraq if that is their aim and it is not in Iran's interests to be hated by Iraqis.
The claim makes no sense. Also it is supported by no evidence. Also it fits the Bush administration line of blaming Iran for everything. I don't see how any serious reporter could repeat it let alone expand upon it in his own voice.
I think what is going on is that Hurst feels the need to balance his reports of dead toddlers (seen with his own eyes) along with the quote "'Ground forces reported they were unaware of any innocent civilians being killed as a result of this operation,' the military said." He knows that innocent civilians were killed and that their deaths were obvious to anyone who cared. Just by reporting what he heard and saw he effectively denounces the US military's contempt for civilian life. I think he felt the need to repeat unsupported accusations against Iran for balance.