Sadr City, the oppressively poor Shiite neighborhood on the north end of Baghdad, is now the front line in the fight create security in the Iraqi capital.
Since September, U.S. troops have been operating together with Iraqi police out of a heavily guarded Joint Security Station on the southern border of Sadr City. In the last two weeks they have started moving north.
About a thousand U.S. and Iraqi soldiers are moving house to house, street by street northward into Sadr City in some of the toughest urban fighting U.S. troops have seen in Iraq.
"In this area there are some real knuckleheads that just want to shoot at Americans," Command Sgt.-Maj. Michael Boom said.
Despite the fierce resistance and the tough conditions they are facing, U.S. troops are giving no ground.
As U.S. troops make progress, Boom said, "they are living in abandoned buildings."
The 50-year-old officer from Sacramento, Calif., admitted he might be too old for this sort of fighting.
"We can't get supply to them," he said. "They come back on their own but we can't push the normal supply lines to them because it would endanger the soldiers. The combat soldiers load up with everything they need to go back out there... drinking water, they're good with it; no bathrooms, no plumbing, very austere conditions."
Iraqi Gen. Abboud Qanbar, the head of the Baghdad Security Plan, and his American counterpart Maj. General Jeff Hammond said during a press conference at JSS Sadr City that they are fighting "criminal gangs."
As they spoke there was a sharp reminder of the fight raging just a few blocks away. A rocket passed overhead. Reporters hit the ground; the generals started to react but then continued talking: just another day on the front line.
The aim of the operation was to put an end to the volleys of rockets and mortars that had been slamming the U.S.-occupied Green Zone in Central Baghdad. Today three U.S. soldiers were killed and 31 Americans were injured in three separate rocket attacks, two on the Green Zone and a third at Camp Rustimiyah in southeast Baghdad.
The U.S. and Iraqi units in Sadr City are also coming under heavy fire as they have moved deeper into the neighborhood, engaging anyone that faces them. Nine Shiite extremists were killed today after U.S. Hellfire missiles targeted them for attacking Iraqi troops.
Lieutenant Col. Dan Barnett, the main battlefield commander, knows the enemy well and said dismissing them as "criminal gangs" doesn't do justice to the sophistication of the opposition American troops are facing.
"These are not just pure, in my opinion, just criminals," Barnett said. "They are clearly organized they have a command and control structure. They have a plan in place. We call them the special groups."
Special Groups is a term used by the U.S. military to suggest Iraqi militias that are trained and supplied by Iran. But who is actually directing the activities of those militias is "the million-dollar question," Barnett said.
"We know some the names of the high-value targets in the area," he said. "We think we know who is pulling the strings on some of these guys. And I guess what we don't know for sure is there a direct link between that individual and [radically anti-American Shiite cleric] Moqtada al Sadr or is he is an agent working on the side just doing his own thing. That's what we are asking."