LINDSEY HILSUM: Another day of war and the unit steps out to clear a neighborhood within Jolan. We pass the previous day's destruction. Iraqi troops are working with the marines. They take up a new position surveying the area.
Opposite us, a school; the unit came under fire from near here yesterday. One of at least eighteen Marines who've been killed so far died here and others were injured.
SOLDIER: We're going to have to knock down part of this wall.
LINDSEY HILSUM: They adapt the place as necessary. A few minutes later they've created a clear line of fire. The mortar teams set up their weapons.
LINDSEY HILSUM: Then they open up not just with mortars but their machine guns, mini grenade launchers, tank rounds, everything they've got.
LINDSEY HILSUM: They're now laying down an enormous amount of fire, taking out the houses all along one road and yet at the moment nothing is coming back. We've heard the occasional crackle of AK-47s, but otherwise nothing.
It seems they really are firing into empty houses. The mortars are meant to saturate the area with lethal fire so anyone hiding behind a wall or in a house is killed or injured. Not all weapons are accurate. This 500-pound bomb was not meant to land 100 yards away -- and shower us all with dust and debris.
As the firing continues, the first captive of the day is brought in for questioning. Prisoners are providing good intelligence. They say they know what they're looking for today because of what they learned yesterday.
The neighborhood has been prepared, so the Marines set off to search building by building. Inside the school, in one of the classrooms, an immediate find.
SOLDIER: 50 caliber rounds. Anti-aircraft.
LINDSEY HILSUM: Nearly every building yields something. The house of Abdullah Junabi, one of the insurgent leaders, is around here somewhere and there has been resistance here in the last few days. They found mortars in this house, a sign that it was occupied by insurgents and now this computer.
It could be perfectly innocent, or it could be a computer which was used to post-messages and videos about hostages like Ken Bigley who are believed to have been held here in Fallujah. They take away the hard disk and documents for the intelligence operatives to work on.
A few doors down, they seize another prisoner. We walk back to the first house where the Marines set up their mortar positions. The captive is brought here, too. He says the gunmen threatened to kill him if he didn't hide weapons in his house, but he says he's not an insurgent.
Most surprising of all, a group of Marines found a family, five children still at home. Iraqi soldiers are talking to them. Their parents said they thought the radio told them to stay at home for their own safety. After such a barrage of fire, their survival seems like a miracle.
MARGARET WARNER: Next, we hear from Dexter Filkins of the New York Times. He's been traveling with a Marine platoon in Fallujah. Terence Smith talked with him earlier this evening.
TERENCE SMITH: Dexter Filkins, tell me what you learned and saw today.
DEXTER FILKINS: It's been a long day. We had a terrible evening last night. I mean, all this is after midnight. It was about... I've been moving in a platoon of about fifty guys and we took about nine... we took nine casualties last night as we moved through city at night.
We hit a house that looked to be booby-trapped. I think there were seven casualties there. We ran into an ambush another time, not very far from that where a soldier was killed and a couple more wounded.
So it was a real meat grinder last night. We captured a mosque after that, in the morning at about 6:00 A.M., a big mosque, in the center of town, actually the biggest mosque. It's called the Great Mosque in the center of... south central Fallujah.
Took the mosque, moved in, set up in there. As we did that, the insurgents started to attack so the Marines basically spent the day fighting off the insurgents. I think they said they killed about 100 of them.
But it was a long day and right at the moment I'm on a rooftop in Fallujah. We've started to move again. We've just paused here. It's around midnight here. We're working our way south again.
TERENCE SMITH: So looking at this over the last several days, this resistance that you're describing now, Dexter, sounds very substantial. Is it actually increasing or decreasing? Is there any trend?
DEXTER FILKINS: There is a trend. I think... I think what everybody agrees on here is that... all the soldiers agree on is that the quality of their people that they're facing and the training and whatnot is growing the further they move south.
We actually heard that before the battle even started some people that we know in Fallujah that that had been their intention, which was to draw the Americans into what they described as a kill zone where they have their best people, you know, their toughest people.
And if they drew the Americans deeper into the city, then they would attack them with their best people. And it certainly seems that that's... that's certainly pattern we're seeing. If you talk to soldiers here, they'll say, you know, they shoot better, they move better, they cover better. It's a lot more difficult now.
I think that what's happening though is if you kind of stand back and look at the map, the insurgents have been moving south and they're beginning to congregate in an area on the southern end of the city.
And so you have, you know, several lines of American soldiers converging on them. And I think it's shaping up. It looks like they could be in pretty... there could be a pretty substantial fight over the next couple of days.
TERENCE SMITH: In fact, there were some reports today of insurgents trying to break out of the southern edge of the city and mix in with the population and try to get away. Do you know anything of that?
DEXTER FILKINS: Well, yeah. The... apparently there's some intelligence. I think there were some intelligence intercepts that I've talked to some people about where the insurgents inside the city are pleading for reinforcements from outside the city and wondering why they haven't come in.
And if you... you know, again if you sort of stand back and look at the map, it's basically and a hammer and an anvil. You've got the Marines moving south as the hammer and then... they're moving south from the north. And then along the south into the city you've got several army units that are forming a block.
And so there is no... there is no back door for these guys and there's no way in for reinforcements. So they're definitely trapped.
TERENCE SMITH: In your article today, you were talking about the insurgents using black flags as a means to communicate and signal one another. Can you explain that?
DEXTER FILKINS: Yeah. I have to say, it's... you know, when you're in the middle of a fight with the Marines here, as I was yesterday and today and you... we were on a roof top at one point taking fire from the ground and I just looked down the street and a black flag had gone up over a water tower.
And then it went away and then another black flag went up further down the street over a mosque. And what we've been told is that the black flag is a signal for the insurgents to gather. Come and fight. There's a fight here.
So it does send a bit of a chill up your spine when you're hunkered down with the Marines fighting and you see these black flags go up because you know more guys are coming in.
TERENCE SMITH: Dexter Filkins of the New York Times, thanks very much for talking to us.
DEXTER FILKINS: Thank you.