The following is from a DoD briefing today with one Colonel Micahel Regner, Operations Officer for I Marine Expeditionary Force, which has been fighting in Fallujah:
The next question, before I continue on to the tactical lay down because I brought up detainees, is yes, there are some foreign fighters in that element. Predominantly, however, most of the 1,052 are in fact Iraqis.
[...]
We can't really identify all of those, but some of our Iraqi brethren which are helping out in this joint effort are saying this guy is clearly from -- let's just say Syria; this individual here is from another country. And so they're helping out. But at this time, out of 1,052 [detainees] most likely about 1,040 or 1,030 are Iraqis.
Math Correction! - A reader points out that the numbers above add up to one or two percent, not .1 percent as I said in the headline. My apologies, especially to Greta, my 8th grade math-teacher. (I went to a crunchy school; we were all on a first-name basis.)