ABU GHRAIB, Iraq — U.S. troops were checking e-mail, lounging in their bunks, doing laundry and contemplating a game of air hockey when the first volley of rockets and mortar rounds struck. Before long, ordnance rained down on the notorious U.S.-run detention camp here. Squads of guerrillas were soon advancing to the walls from several directions in what appeared to be a highly scripted assault.
Prisoners rioted as if on cue, eyeing the opportunity for a mass escape. A thunderous suicide truck bomb struck near the southeast guard tower, knocking it out of action and sending a roiling, black cloud into the dusky sky. Some GIs contemplated the unthinkable: The place could be overrun.
"I thought it was, like, we were going to start defending the Alamo," recalled Sgt. Maj. Chris Rodriguez, a military policeman. "I thought they had busted down the walls."
The audacious attack in early April was ultimately thwarted, and its clear aim -- a sensational escape of some of the 3,400 detainees -- was not achieved. But the guerrillas did score a public relations coup by striking a facility that had become synonymous worldwide with prisoner abuse.
Moreover, for U.S. authorities, the lessons learned from what may have been the largest insurgent operation in Iraq to date still resonate. For example, closer attention to unusual insurgent movements in the area that afternoon could have signaled that something big was coming, said a senior military official in Baghdad who had studied the strike.
Since the attack, guerrillas have mounted other sophisticated operations, although none on the same scale. In recent weeks, they have organized two or more synchronized suicide car bombings and set up multilayered roadside ambushes. Nine days after the incident at Abu Ghraib, guerrillas about 200 miles to the west attempted to overrun a Marine base near the Syrian border, deploying dozens of foot soldiers and two suicide-attack vehicles, including an explosives-laden firetruck.
U.S. authorities are concerned that a similar-sized strike may be in the planning stages, aimed at targets in or near Baghdad that include a military base, a government installation, the fortified Green Zone or Abu Ghraib again. "We believe the enemy is ... looking for the opportunity to have large-scale, coordinated attacks," the U.S. military official said.
The military estimates that on April 2, insurgents marshaled a company-sized assault, using as many as 200 fighters and launching related strikes in the area that evening. At least three vehicles driven by suicide bombers were deployed.
The event underscored the fact that Iraq's insurgents retain the ability to surprise the U.S. high command, which has enlisted a multitude of experts to help overcome its spotty intelligence -- without great success.
"We've had the Northern Ireland guys ... we've had every expert from Vietnam come out of the woodwork to be talking heads," a senior U.S. military intelligence official told reporters in Baghdad. "But I've got to tell you, it's all, `Blah, blah, blah,' and I'm not sure any of it fits right now. They're scratching their heads and trying to figure this out too."
The assault made clear again the folly of underestimating an enemy once dismissed by Pentagon officials as "dead enders."
Iraqi guerrillas have used weapons that range from World War II-era rockets arrayed in donkey carts to sophisticated antiaircraft missiles. They've regrouped after massive U.S. assaults on Fallouja and other towns and the arrests and killings of thousands of fighters; circumvented high-tech jamming devices designed to cripple electronically detonated roadside bombs; infiltrated military bases and the Green Zone; and generally displayed a level of resolve and skill -- however brutally applied -- far beyond anything that U.S.-trained Iraqi forces have shown.
"We're operating against a thinking enemy, clearly," Marine Gen. Peter Pace, vice chairman of the Joint Chiefs of Staff, said last week in Washington. "The enemy has changed their tactics, techniques and procedures in response to what we've been doing."
The attack at Abu Ghraib spotlighted insurgents' chilling ability to mount synchronized operations that involve heavy shelling, diversionary tactics and infantry thrusts in coordination with suicide vehicles. Highly trained former officers in Saddam Hussein's military probably designed the Abu Ghraib attack over a period of weeks, U.S. military officials say, and conducted close surveillance of Abu Ghraib. The detention center sits just west of the capital in the heartland of Iraq's Sunni Muslim Arab population, the insurgency's driving force.