URBAN JUNGLE.

The U.S. military is conducting urban warfare exercises for the brigade of the 10th Mountain Division, which launched a 12-hour, simulated house-to-house assault in the dark of night here at the Army's Joint Readiness Training Center. The mission was declared a success, but the numbers were grim: Of the 146 Alpha Company men who led the assault on the city, only 14 remained standing at daybreak. Officially, the battle was for Shughart-Gordon, a phantom city of 29 plywood and cinder block buildings named to honor two Army Delta Force soldiers killed in Somalia in 1993. The Bush administration's declaration that Iraq was in "material breach" of United Nations Security Council resolutions makes a second Gulf War ever more likely. So the military's stepped-up training in urban warfare could be crucial to prying Iraq from Saddam Hussein's grasp. Defense and intelligence officials say Iraq's poorly trained Army and ragtag Air Force pose little threat to the U.S. military in the desert, so they believe Saddam will take the battle into cities like Baghdad and Tikrit. It is on those streets where a disparate collection of Iraqi paramilitary units may await U.S. forces. In addition to three armored Republican Guard brigades encircling Baghdad, Saddam is believed to have 12,500 of his elite Special Republican Guards protecting key locations inside the city. The Saddam Fedayyeen, a thuggish group of soldiers commanded by Saddam's son Uday, and Iraq's Special Security Service are also expected to remain loyal until the end. And U.S. officials are particularly concerned about the Mujahedin-e Khalq (MEK), a well-drilled army of 5,000 Iranian dissidents Saddam has trained to launch strikes over Iraq's eastern border.