I just conducted my interview this afternoon with al Qaida expert Peter Bergen, the author of Holy War, Inc.: Inside the Secret World of Osama bin Laden.

We plan to publish the interview tomorrow evening.

One thing that caught my attention was Bergen's comments on the identity of the foreign jihadists now operating in Iraq and why they're there. According to Bergen, the majority of them are Saudi militants -- numbering as many as a few thousand -- who've come into the country not through Saudi Arabia but through Syria.

Now, why these guys would want to go into Iraq to kill Americans might not seem like much of a mystery. But there may be as much of a push as a pull. According to Bergen, the current Saudi crackdown against Islamic militants is actually quite fierce. And he says that many of them are fleeing Saudi Arabia because of it. Ironically, the crackdown on Islamist militants in Saudi Arabia may be leading to an upsurge of their numbers in Iraq.