Mahdi Army militia members have stopped wearing their black uniforms, hidden their weapons and abandoned their checkpoints in an apparent effort to lower their profile in Baghdad in advance of the arrival of U.S. reinforcements.

"We have explicit directions to keep a low profile . . . not to confront, not to be dragged into a fight and to calm things down," said one official who received the orders from the anti-American Shiite cleric Muqtada al-Sadr.

. . . The decision by al-Sadr to lower his force's profile in Baghdad will likely cut violence in the city and allow American forces to show quick results from their beefed up presence. But it is also unlikely in the long term to change the balance of power here. Mahdi Army militiamen say that while they remain undercover now, they are simply waiting for the security plan to end.

. . . Across the capital residents described a changed Mahdi Army - in Sadr City, a Shiite slum of more than 2 million people, in Talbiyah on the outskirts of Sadr City, and in Hurriyah, a formerly Sunni Muslim neighborhood in the north of the capital that in recent weeks has been taken over by the Mahdi Army.

Checkpoints in those locations were gone. Instead, young men in jeans and buttoned shirts directed traffic, helped the Iraqi army and wandered the streets nonchalantly.

ID checks for Sunni names like Omar have been replaced by a sort of Shiite code.

"Mawlak?" a Mahdi Army member will inquire. "My master?"

A Shiite will answer, "Mawlak al Hussein" - "My master is Hussein," referring to a revered Shiite saint. They check for the Shiite accent common in the south versus the Baghdadi accent of the Sunnis.

NBC News' Andrea Mitchell reported on MSNBC that Saudi Arabia is mulling whether or not to send troops to Iraq, to "protect their interests" there.