The suspected homicide attack (search) inside an Army mess hall in Iraq (search) represents a breach of the most basic principles of military security and points to significant weaknesses in the screening of Iraqis who are allowed onto the base, experts say.
"This is an incredible occurrence, that someone could have come in undetected with some kind of bomb," said Mitch Mitchell, a retired Army officer who helps design security training for the military. "It blows my mind that force protection on the base is that poor."
Tuesday's explosion at a base near Mosul (search) killed 22 people, including 14 U.S. service members, injured scores more and put Pentagon officials on the defensive against new criticism of holes in the protections for troops in Iraq.
Gen. Richard Myers, chairman of the Joint Chiefs of Staff, defended the security plans put in place by the U.S. commander in northern Iraq, Brig. Gen. Carter Ham.
"We have had a suicide bomber apparently strap something to his body and go into a dining hall. We know how difficult this is, to prevent people bent on suicide and stopping them," Myers said Wednesday at a Pentagon news conference. "This was the insurgents that did this. So it's not General Ham that attacked his dining hall."
Military officials initially said a 122 mm rocket was the likely cause. Myers would not comment on specific evidence in the ongoing investigation of the attack, but said, "If it was a rocket, you'd find remnants of the rocket. If it were an improvised explosive device you would find remnants of the improvised explosive device."
Like Myers, Defense Secretary Donald H. Rumsfeld defended U.S. troop security in Iraq, saying it was "an enormous challenge to provide force protection."
"They have to be right 100 percent of the time," he said, standing at Myers' side. "An attacker only has to be right occasionally."
Elsewhere in Iraq, an international construction company, Contrack International Inc., which led a coalition of firms working on a $325 million contract to rebuild the country's roads, bridges and railways, withdrew from that contract last month after a surge in attacks on reconstruction efforts, Lt. Col. Eric Schnaible of the Pentagon's Project and Contract Office in Baghdad, said Wednesday.
"It's hard to do construction in a place where people are shooting at you or intimidating your work force," Schnaible said in a telephone interview. "It's a challenge across the country."
Mitchell and other experts said it was obvious the military was not taking basic protective actions for U.S. troops in Iraq. On most bases, troops have their meals in large dining hall tents like the one attacked Tuesday, for example, instead of in small, scattered groups. That presents a tempting target for insurgents, Mitchell said.
"It shows you the level at which force protection was addressed on that base, and it wasn't very high," said Mitchell, an analyst with the Institute for National Strategic Studies at the military's National Defense University.
Rumsfeld said he was saddened that anyone could believe he was not fully committed to security for U.S. forces. Still, he said the explosion should be put into the context of the larger war.
"I mean, think about the murders that take place in every major city in the world. One could say, 'Well, why aren't they stopped?' ... And they are terrible things. And the loss of life is heartbreaking and it's a normal human instinct," Rumsfeld said.
"But the other way to think about it, or an additional way to think about it is, think about turning that country over and letting them win, those people who are doing those things. It would be a terrible loss for civilized society," the defense secretary said.
The explosion was the deadliest single attack on U.S. forces since the March 2003 invasion of Iraq.
A radical Sunni Muslim group, the Ansar al-Sunnah Army, has claimed responsibility for the attack.
Infiltration of insurgents onto U.S. military bases has been a concern for some troops in Iraq, particularly because of the fighters' ability to penetrate the Iraqi security forces.
For example, the former police chief in Mosul was arrested by Kurdish forces last month after a wave of insurgent violence in the city. Kurdish officials said the former chief had turned over some police stations to insurgents. At the time of the November violence, U.S. military spokesmen said they believed some Mosul police officers were working with the insurgents.
In October, 50 new Iraqi soldiers were killed shortly after they finished their U.S.-sponsored training. An Iraqi official who warned that the incident showed insurgents penetrated the Iraqi security forces was assassinated a week later.
Besides Iraqi soldiers and other security officers, Iraqis enter U.S. bases as workers for the civilian contractors which handle functions such as food service, laundry and trash collection. Weeding out insurgents from those workers should be a priority, said military analyst Michael O'Hanlon of the Brookings Institution think tank.
"We have to work with Iraqis, and employing them has to be part of any reconstruction plan. So we will be vulnerable, but we don't want to have dozens of people vulnerable at the same time," he said.
Anthony Cordesman of the Center for Strategic and International Studies said the U.S. forces must be careful not to completely separate themselves from the country's civilians.
"If you want to work with Iraqi allies and win this war politically, you can't separate the U.S. forces from the Iraqis," said Cordesman, a frequent critic of U.S. tactics in Iraq.