"One Iraqi who witnessed the carnage said the even Saddam had not used that kind of firepower in Karbala."
Well, that's really going to repair the damage to our reputation. It seems that the machine inertia is on the side of the Bushist demand to "kill and capture" al-Sadr. (I still can't believe they really said they would kill him and capture him.) This also had a bearing on the departure of the Spanish army - (link) - apparently the US command wanted them to thrash into Najaf, an operation their intelligence on the ground suggested was foolhardy. The Spaniards requested guidance from Madrid, where international lawyers for the government concluded that a major offensive operation would be incompatible with UN Security Council Resolution 1511, the legal basis for their presence, and should be left to the official Occupiers. And, their officers added, should not militarily be attempted!
"The highest-ranking Spanish military officers in charge in Iraq sent a report at the beginning of April to the North American command in which they observed that increased harassment of Al Sadr and his devotees would aggravate the situation in Iraq and would provoke "a large-scale military operation"."
And that's exactly what they got: here.
"Tuesday night, the Americans made a high-risk gamble by trying to breach the Mukhaiyam Mosque, situated just west of the Shrine of Hussein. The attack was one of the largest operations carried out in the past year by the First Armored Division, which until now was responsible for controlling Baghdad. Fighting raged on all sides of the mosque, with soldiers scrambling through rubble-strewn streets and ducking sniper shots and rocket-propelled grenades.
The Americans relied heavily on the devastating cannons and machine guns of their M-1 Abrams tanks and Bradley fighting vehicles, which pounded surrounding buildings, setting many on fire."