WASHINGTON — The explosion that killed 22 people in a U.S. military mess hall in northern Iraq was apparently an inside job by a suicide bomber who managed to bypass multiple layers of security, senior military officials said Wednesday.
U.S. military investigators concluded that the blast near Mosul on Tuesday was caused by a suicide bomber rather than a rocket after finding remnants of material that might have served as the assailant's backpack or vest, as well as widely dispersed body parts that probably belonged to the bomber, a senior military official said.
In the deadliest attack on a U.S. military base since the war began in March 2003, the bomber apparently packed ball bearings around a bomb strapped to his body to maximize the amount of shrapnel that tore through the crowd at noon, when the greatest number of soldiers would be present, said the official, who spoke on condition of anonymity.
Military officials described their findings after a briefing by Defense Secretary Donald H. Rumsfeld and Air Force Gen. Richard B. Myers, chairman of the Joint Chiefs of Staff. Rumsfeld, in unusually somber remarks, also sought to alleviate criticism that he had treated troops and their families callously.
"I -- and I know others -- stay awake at night with concern for those at risk, with hope for their lives and for their success," he said, his voice cracking during opening remarks that he prepared himself. "And I want those who matter most -- the men and women in uniform and their families -- to know that."
Tuesday's attack occurred amid a rising campaign of intimidation by insurgents ahead of a national election set for Jan. 30.
Rumsfeld, warning that the election would not end the violence, echoed comments made by President Bush earlier in the week that the insurgents were having an adverse effect on efforts to stabilize Iraq.
"I think looking for a peaceful Iraq after the elections would be a mistake," Rumsfeld said. "I think our expectations level ought to be realistic about that."
Bush has had to defend Rumsfeld after the Defense secretary delivered what many considered to be a rebuff to a National Guard specialist who complained about inadequate protective equipment and after revelations that Rumsfeld used a signature machine for letters sent to families of slain troops. A CNN/USA Today/Gallup survey this week found that 52% of Americans believe Rumsfeld should resign.
Military officials said 14 U.S. troops, four U.S. civilian contractors and three Iraqi national guardsmen were killed in the attack, along with one unidentified "non-U.S." victim, apparently the bomber.
Sixty-nine people were wounded. They included 44 U.S. troops, seven U.S. contractors, five U.S. civilians working for the Defense Department, two Iraqi civilians and 10 contractors of other nationalities. The nationality and occupation of one could not be determined, officials said.
Dozens of victims arrived Wednesday at the Ramstein Air Base in Germany. Eight patients were listed as being in critical condition. Others had shrapnel cuts, broken bones and other non-life-threatening injuries. About 25 returned to duty, defense officials said.
"At this point it looks like it was an improvised explosive device worn by an attacker," Myers said at the Pentagon briefing. "If it was a rocket, you'd find remnants of the rocket."
The investigation is continuing, but the disclosure that a suicide bomber was responsible for the attack contradicted early reports that a 122-millimeter rocket struck the fabric-covered tent at Forward Operating Base Marez.
"We will determine exactly what happened at FOB Marez and continue to work to ensure the safety and security of our people and our operating bases," Army Gen. George W. Casey, commander of the U.S.-led multinational force in Iraq, said in a statement.
The attack was the second time a suicide bomber managed to infiltrate a heavily fortified U.S. compound.
On Oct. 14, two suicide bombers detonated explosives-laden backpacks inside Baghdad's heavily barricaded Green Zone, killing six people and injuring more than 18. The area houses the interim Iraqi government and the U.S. and British embassies.
In a statement on an Islamic website, a group called the Ansar al Sunna Army claimed responsibility for the attack and said it was a suicide operation executed by a 24-year-old man who had worked at the base for two months. Military officials said they did not dispute the account, but also couldn't confirm it.
Officials at the base have been worried about the possibility of an attack since late November, when a suspect arrested in a roundup in Mosul's Old Town was found with a document that contained minutes of a cell meeting that described an attack on U.S. forces, according to an ABC News report.