Now, over at Kaboom! (officially the Colby Buzzell of 2008), here's some corroboration.
Day 2: I stand in the streets, looking at a building with a sloping roof and two cannonball-sized holes in the middle of it. We have spent many hours zigzagging through the various Shi’a neighborhood cores in Anu al-Verona, but it is only now, with the light of the morning, that the full scope of JAM’s resurgent spectacle is comprehended. The aforementioned holes are the gift of an Iraqi Army’s BMP (armored personnel carrier) main gun, and the aforementioned building is the local Sawha headquarters. The one Son of Iraq who bothered to show up for work today expresses his displeasure with the situation. I thank him for his devotion to duty and ask him where his coworkers are. He looks at me like I have a dick growing out of my forehead and says, “they are at home, of course. It is not safe here.” I ask him why he isn’t home then. “Because my father kicked me out and told me to go to work and I have nowhere else to go.”
My bold. OK, so not only did some members of the Iraqi Army go over to the other side, but these ones took their BMP with them - and immediately turned its guns on the ex-NOIA guys, with the result that they made themselves scarce (or possibly set off for the nearest concentration of Shia for some revenge). There have been reports scattered around of the Sadrists capturing armoured vehicles from the government, but most have referred to Humvees and such; this is the first heavy armour to be mentioned.
It can be pretty heavy, too; the BMP-3, despite ranking as an infantry fighting vehicle, carries a 100mm gun. I don't know which version we supplied to the Iraqi government (I think the armour came from Hungarian stocks). Meanwhile, Des Browne says:
At one point, he said, British tanks, armored vehicles, artillery and ground troops were deployed to help extract Iraqi government troops from a firefight with Shiite militiamen in the city.
Extract; as in "cover the retreat of", "aid in escape of", or just "save" them. It's Sadr's move, it always has been; as far as I can see, the only meaningful exit strategy has always been to recognise the people with actual mass support, so NOIA in the Sunni sector and Sadr in the Shia sector. Half of this has actually been done, although nobody wants to admit it; the problem is that their territories overlap. Lieutenant G's area of responsibility is exhibit A; he's far enough north to have 1920 Revolution Brigade NOIA on his side, but this doesn't mean he doesn't also have a major Sadrist presence.
Extra points: did anyone else spot Chalabi claiming credit for the ceasefire?