Arraf: Falluja 'has been breached'
CNN Baghdad bureau chief Jane Arraf
Battle for Falluja, bombings in Baghdad.
U.S. and Iraqi forces begin their assault on Falluja.
Interim Iraqi leader Ayad Allawi authorizes Falluja assault.
FALLUJA, Iraq (CNN) -- About 10,000 U.S. and 2,000 Iraqi forces began an assault on Falluja on Monday, aimed at driving insurgents from the city.
CNN Baghdad bureau chief Jane Arraf is embedded with the U.S. Army there; she spoke with "Anderson Cooper 360°" guest host Heidi Collins on Monday night by telephone.
ARRAF: At this point, the offensive has been going on for hours. And -- I'm not sure if you hear those thuds in the background -- the sky just lit up over the city of Falluja. There are continued airstrikes and ground strikes.
Quite a heavy bombardment as forces here ... try to soften up the insurgents to move further into the city. We started out on the northeast corner, where they found what they had expected and feared, which was a string of improvised explosive devices -- booby-trapped -- waiting for the troops to come in.
In that sector, [there were] very few civilians. And we had been told that they had not been allowed in that sector by the insurgents who have been rigging these homemade bombs around the city. The battle continues, and is expected to continue for some time. All the soldiers going into this -- and this is a massive effort -- have been told that this is a historic battle; this is their chance to rid the country of the insurgency.
COLLINS: You talk about the resistance, you talk about the foreign fighters. Any more you can tell us about that, as far as characterizing the size of it and how intense it is?
ARRAF: Military officials are putting varying figures on how many men they believe they're fighting ... and they vary from 1,200 to 3,000.
On the lowest tier -- although a lot of these probably would have fled the city by now -- it's people who are doing it just for the money. They are unemployed, perhaps angry, young men, and they get a few dollars for shooting a rocket-propelled grenade.
There are extreme religious fundamentalists, who are doing it because they believe that it is their religious duty. ...
There are former Baath Party elements, which are a large part of this -- this is a Sunni stronghold and a very conservative city. And there are the foreign fighters, probably fewer than had first been believed, but this city, over the past few months -- since the end of the war, in fact -- has become a magnet for insurgents of all sorts, a breeding ground for different cells. And many military officials believe that it has become a command-and-control center for the entire insurgency in Iraq.
COLLINS: We know that earlier in the day the troops were able to take over one hospital and two key bridges. Again, in talking about this resistance, are they able to take over more positions of importance, or would you say they are at a standby or a standstill as of late?
ARRAF: They're not at a standstill so much. They are certainly going forward. ... We're not entirely clear as to what targets they may have taken in other sectors of the city. Certainly, they had a lot of objectives. And the Iraqi security forces are playing a large part in that.
Those are the people -- we are with, for instance, Iraqi commandos -- and the Iraqi security forces, the intervention forces, are the ones who are going into places like mosques and schools, where U.S. forces say they've been targeted from.
As for the major targets that they have, most of those [involve] access to the city, and the city has, indeed, been breached.