Dozens of people have been detained by the U.S. and Iraqi militaries as the press forward with an offensive near Samarra. More than 1,500 troops are deployed in what the military is calling an anti-insurgency sweep. Renee Montagne talks to BBC reporter Jim Muir. An Iraqi girl looks at an Iraqi soldier securing an area in al-Dor, north of Baghdad, on Friday. U.S. and Iraqi forces are in the second day of a vast sweep -- called Operation Swarmer -- to root out insurgents. 
RENEE MONTAGNE, Host: This is MORNING EDITION from NPR News. I'm Renee Montagne.</s>RENEE MONTAGNE, Host: In Iraq, a joint U.S.-Iraqi operation is continuing north of Baghdad. The offensive is dubbed Operation Swarmer and is aimed at rooting out insurgents near Samarra. That's the city where last month's massive bombing of a revered Shiite shrine touched off weeks of sectarian violence and brought fears of a civil war in Iraq.</s>RENEE MONTAGNE, Host: The U.S. Military is providing little information about the offensive. General John Abizaid of the U.S. Central Command said it's not a big departure from normal operations. But it is known that 50 helicopters and some 14 hundred troops are involved.</s>RENEE MONTAGNE, Host: The BBC's Jim Muir joins me now from Baghdad. What more can you tell us about this operation? It's being described, as I just said, as the biggest air assault since the invasion of Iraq three years ago.</s>JIM MUIR: Well, that's why we're talking about it, because it has been described as the biggest air assault. But what that means is simply that the largest number of helicopters have been used to ferry in the troops for this operation, a larger number than in any similar campaign in the past three years, is what they're saying.</s>JIM MUIR: But they're also saying there has been no firing from the sky, none of those helicopters, according to the U.S. military, have been actually involved in rocketing or firing bombs at insurgents. In fact, one of the American commanders in the area on the ground is being quoted as saying they've had no contact with insurgents. There has been a lot of over-expectation emanating from that initial announcement about this being the biggest air assault in the past three years. And the troops involved are now being scaled down from 1,500 to just 900.</s>RENEE MONTAGNE, Host: Do we know the targets and where it's being concentrated?</s>JIM MUIR: The focus is on this area of wasteland to the northeast of Samarra. Now of course, that's an emotional motive word now, Samarra, because it's where there was the destruction of the Shiite shrine last month, triggered a whole wave of sectarian reprisals between Shiites and Sunnis. So that is the geographical location, in part, perhaps, of the context, and also a lot of the interest of this operation.</s>JIM MUIR: In that area, obviously, there has been insurgent activity. The U.S. Military says that six arms caches, bombs and also insurgent materials, have been found. So there is, obviously, some kind of insurgent presence there, but quite hard to get at. It's much more dispersed.</s>RENEE MONTAGNE, Host: Just very briefly. This comes at a time when the U.S. military is seeking to reduce its military profile in Iraq. What does this suggest?</s>JIM MUIR: I think this comes at a time when the Americans are struggling to find the right way out for the military, both politically and militarily. It's a time of great soul searching. But also, we're just coming up for the third anniversary of the war to overthrow Saddam. The American military machine is well aware that all the journalists are preparing anniversary pieces.</s>JIM MUIR: So I think this operation was perfectly normal in operational terms, but that it has got a political spin on it to show that the U.S. military is not just sitting here taking casualties, being bombed by insurgents. It is getting out there and trying to get to the roots, to cut out the roots of the insurgents.</s>RENEE MONTAGNE, Host: The BBC's Jim Muir in Baghdad, thanks very much.</s>JIM MUIR: You're very welcome.