ABC news reports that US Secretary of State Condoleeza Rice has expressed concern to the Shiite-dominated Maliki government that the "surge" so far as targetted Sunni neighbourhoods, overlooking Shia hotspots including Sadr City.
"The Iraqis, however, told her that the Mahdi Army and its leader Muqtada al-Sadr had been losing influence and were cooperating with authorities on security issues, the official said.
"The Iraqis said they did not want to 'waste our resources in a place that's stable,' the official added.
"He did not say how Rice responded.
"Before the operation began, U.S. officers said privately that the Shiite-dominated security forces were resisting calls to move against al-Sadr's forces quickly, arguing that the main threat to stability came from Sunni insurgents."
If the US and Iraqi security forces don't move against al-Sadr's militias, the surge will be plainly sectarian and risks leaving Baghdad's Sunni population largely defenceless once it's over.