The Los Angles Times on Apr. 5 wrote: Iran’s role in Iraq is going to be a huge question and topic of debate this coming week. On Tuesday and Wednesday, Gen. David Petraeus, head of the military mission in Iraq, and Ryan Crocker, head of the U.S. Embassy in Baghdad, will speak before Congress about the situation in Iraq.

A couple days ago, Ryan Crocker spoke to reporters in Baghdad about Iranian involvement in Iraq. He said he couldn’t say whether Iran brokered any deal…
Instead, he accused Iran of being behind the incessant barrages of rockets and mortars that land on the U.S.-protected Green Zone, the administrative headquarters of Baghdad:
[It’s] very clear to us here, because we got the fins of – the tail fins of what was dropping on us, very clear to the prime minister down in Basra, because they were dropping on him, too. And this was, quite literally, made in Iran. All of this stuff was out of Iran, and a lot of it, you know, manufactured in 2007.
And he went further, you do wonder if, when Iranian munitions start flying all over the place…

Petraeus, too, has been ramping up the rhetoric on Iran. In an interview with the BBC late last month, he also accused Iran of being behind the recent attacks on the Green Zone:
Some see a significant shift in such remarks, indicating the imminence of a tougher stance toward Iran.