Block to block combat

A US soldier fired an anti-tank rocket at the second floor of a darkened school building, blasting an entry to get at snipers barricaded there. But as troops climbed a ladder to the hole, half a dozen were killed in a flash of mortar fire. Several more collapsed in the courtyard, picked off by the snipers.

Rising from the mangle of debris and concertina wire were the electric screams of Led Zeppelin, broadcast by the US military in between warnings that civilians should take shelter - "It's been a long time since I've rock and rolled ...," then, "Stay calm. We are here to protect you."

In a chaotic night of urban warfare, a remnant US force "liberated" a small city, but at the cost of killing civilians, razing large buildings, and losing dozens of its own. When day broke over the concrete battlefield, the streets were hazy with green and purple smoke and littered with bodies and crumpled vehicles.

Fortunately, this battle was bloodless, waged with lasers and pyrotechnics rather than live bullets and artillery. Hundreds of light infantrymen from the 10th Mountain Division, backed by armored units, fought their way through a mock city rising from the Louisiana swamps in the toughest urban training the US Army offers. Military observers give this unit high marks: On most assaults, losses are even higher.

Yet US ground troops may soon face a real-world test of their block-to-block combat skills: a battle for Baghdad. Iraq's elite Republican Guard units are erecting concentric rings of defense around the city of 5 million. Outmatched in a desert tank war, Iraqi leader Saddam Hussein is apparently planning to hold out in cities and lure US forces into a deadly urban struggle.

American military officers acknowledge that a drawn-out battle in Baghdad would erode US superiority and likely present agonizing scenarios and heavy casualties. "Baghdad would be incredibly hard, sort of like attacking Los Angeles," says Capt. Rick Roper, who coaches some of the thousands of troops mounting urban assaults here at Fort Polk each month.

This mock battle underscores the harsh dilemmas US soldiers may face: How to overcome Mr. Hussein's home-turf advantage in defending sprawling cities without becoming trapped? How to balance the risk to civilians against dangers for US troops - especially when Iraq has threatened to use human shields?

Inside Iraqi cities, military operations would be vastly more complicated. Buildings constrict troop and tank maneuvers, interfere with radio communications, and limit close air support from helicopters and gunships. Dense populations make airstrikes - even precision ones - costly in civilian lives. From sewers to rooftops, cities are multilayered, like three-dimensional chessboards, creating endless opportunities for ambushes and snipers. Worse, Iraqi forces defending the cities could try to halt invading troops by shelling them with chemical weapons.

"Urban warfare is ... close, personal, and brutal," says an Army report. "Tall buildings ... sewer and storm drains, allow unobserved shifting of forces, and streets become kill-zones."

Brutal as it may be, urban conflict is increasingly likely, military commanders say. More than 75 percent of the world's population is projected to be living in cities by 2020. As a result, the Pentagon has intensified urban training while drawing lessons from recent US military actions in Somalia, Haiti, Panama, and the Russian fight for Grozny, Chechnya.

New urban-war doctrine depends more on sophisticated reconnaissance and high-tech weapons that destroy targets with unprecedented precision. In World War II and Vietnam, capturing a city often meant reducing it to rubble in a massive frontal attack. "We can't just bomb everything. This is not Stalingrad," says Csm. Sean Watson of the 10th's 1-87 battalion.

The more calibrated use of force is also necessitated by the downsizing of the US military, officers say. "It takes an incredible number of troops to control a city," says Maj. Paul Wille, executive officer of 1-87. "We've gotten so small, we have to attack with an economy of force."

Now, thousands of infantrymen each month are testing their urban-warfare skills in an 80,000-acre, $1 million-a-day "box" at Fort Polk, La. For many, it could be the last major exercise before deployment. Their objective: Capture Shughart-Gordon, a 29-building mock city named after two Medal of Honor recipients killed while trying to rescue soldiers from a downed Black Hawk helicopter in Mogadishu.

"This is the best simulation you can get," says Lt. Col. Skip Lewis, whose 500-strong battalion poses as insurgents defending the city. Soldiers are equipped for a complex form of laser tag. Still, training is limited in destruction and scope, and lacks simulated chemical attacks.

During a rigorous, two-week rotation here last month, 3,200 troops from the 10th Mountain Division's 1st Brigade, led by Col. Burke Garrett, practiced operations they would use, on a larger scale, in Baghdad.

The day before the attack, inside a heated canvas tent in a clearing a few miles from the city, officers crowd around a dry-erase board for the latest intelligence reports. "A broken vehicle is blocking the western entrance," an officer says. Enemy troops, tanks, and minefields are spotted. A bridge has been blown up.

Leveraging rapid or real-time intelligence is critical to US urban strategy today. Using scouts, satellite imagery, and sometimes detailed blueprints, battle planners try to pinpoint which buildings, even which floors, the enemy will defend. What sectors of the city could trap US troops? What are the best sniper positions?

That night, Colonel Garrett orders airstrikes on three multistory buildings key to enemy defenses. Airstrikes on military headquarters, utilities, communications nodes, and defensive positions are aimed at isolating and weakening the enemy before an urban assault. "We have to take the fight out of them," says Major Wille.

Meanwhile, hundreds of troops begin an all-night march through swamps, waist-high creeks, and dense woods. Their mission: pave the way for attack by securing key roadways and bridges on the city's perimeter. As the arduous night movement demonstrates, a major part of taking over a city is just getting there.

A burst of rifle fire shatters the silence of moonlit wetlands. Then another. The enemy ambushes a platoon slowed by overgrowth. Minutes later, mortar rounds finish them off. "We have mass caz [casualties]!" a wounded platoon leader yells to his radioman. The shrill whine of laser detectors rises from the 20-odd casualties scattered through the woods.

"Pretty much the entire first platoon is wiped out," 1-87 Charlie Company commander Capt. Eric Lopez radios to his headquarters. "Should I push forward with third platoon or secure this area and caz-evac [evacuate] them?"

Cold, wet, and sleep-deprived after days in the field, the men make their final approach. Faced with scores of casualties, less experienced soldiers take charge. Exhaustively rehearsed plans fall apart in the chaos. It's a pattern familiar to veteran commanders, who instill the idea that the key to war fighting - and urban warfare especially - is flexibility within control.

"The enemy has a vote here, gentlemen," 1-87 battalion commander Lt. Col. Paul LaCamera cautions soldiers gathered in a muddy encampment on the eve of the attack. "As soon as the enemy votes, erase the white board."

An hour into the night attack, the board is wiped clean. A convoy of soldiers in five-ton trucks takes the wrong road. Halted by a minefield, it fails to deliver troops in time to secure a landing zone for helicopter assault forces. Next, the landing zone comes under heavy fire.

"Zero 6 Romeo this is one seven, what is your instruction?" a radio officer asks as forces are rerouted across the battlefield. The glitch is one of several that delay the main assault. Indeed, coordinating firepower and the flow of troops to penetrate enemy defenses at a single point - "the breach" - and gain a foothold in a few buildings is one of urban warfare's most complex tasks.

"Go! Go! Go!" a sergeant yells as a soldier dashes from the side of a cinderblock building.

Obscured by a smoke grenade and sheltered by covering fire, the soldier drops to the ground and struggles to cut a spiral of concertina wire. But before he breaks through, a round of sniper fire strikes him from an upper-story window.

Moving between buildings is one of the most dangerous maneuvers, as witnessed by the bodies lining the walls at Shughart-Gordon.

To improve "survivability," light infantry are training more in cities with armored units. Foot soldiers protect the flanks of armored vehicles from grenades and explosives called satchel charges. Tanks provide shock value, thermal-imaging night vision, and long-range firepower.

Still, this symbiotic relationship is hard to achieve. This night, at least one Bradley is blown up by a satchel charge when too few ground troops guard it. Armored vehicles can also mistakenly crush foot soldiers, as happened in training here last fall when two men died.

Close air support for troops in cities is also limited. Kiowa helicopters circle the battlefield, but cannot spot targets amid smoke and clutter. Once troops begin entering buildings in small teams, survival depends on swift reactions.

A team of four soldiers "stacks up" along the police-station wall. On a signal, the first pivots through the doorway pointing his M-4 carbine, and yells "Freeze!" The others follow. Within seconds, though, all fall to enemy gunfire.

Rule No. 1 for clearing a building: Avoid doorways and stairwells - "fatal funnels" that are often booby-trapped. Instead, blast your own entry. Rule No. 2: Clear from the top floor down. "Going up a stairway is a death trap," says 1st Sgt. Stephen Travers, his face smeared with camouflage. "All someone has to do is toss a grenade down, and you're done."

Soldiers must also make split-second decisions on whether a room holds friends or foes.

"Eeeee!" Female clerks held hostage in the post office shriek as US troops storm in. One soldier hesitates and is gunned down by an enemy fighter hiding in the back room.

As rifle fire dwindles and sun lightens the sky, one insurgent, Pfc. Jeff Gritz, surveys the scene. The 10th Mountain Division performed well, he says. "They were almost sneaky like us."

As for the specter of civilian casualties, Private Gritz, like many of the soldiers, has no clear answer. "What can you do? There is a guy shooting over a pregnant lady's shoulder. The Iraqis strap kids to tanks. What can you do?"