At the Pentagon, General George Casey, the top US military leader in Iraq, was also asked about the Lancet study.

Gen. George Casey: “I have not seen the study. That 650,000 number seems way, way beyond any number that I have seen. I’ve not seen a number higher than 50,000. And so I don’t give that much credibility at all.”

• Reporter: “What’s the 50,000 number? Where did you see that from?”

Gen. Casey: “I don’t remember, but I’ve seen it over time.”

Reporter: “Is that the U.S. military estimate?”

Gen. Casey: “I don’t remember where I saw that. It’s either from the Iraqi government or from us, but I don’t remember precisely.”

Meanwhile, one of the nation’s leading pollsters is backing the study’s findings. In an interview with CNN, John Zogby of Zogby International said he believes the researchers’ methodology is sound and their conclusions accurate.