The Marines were on a foot patrol near Al-Fallujah when the bomb exploded.
Usually U.S. troops on patrol are well spaced out to limit casualties. But the high death toll on 1 December suggests they were either too close together -- or that this was an extremely powerful blast.
"We are saddened by the loss of life, whether it's one soldier who loses his or her life or 10 or 11, we are saddened to hear that news," White House spokesman Scott McClellan said in Washington. "Our hearts and prayers go out to the families. Their loved ones paid the ultimate sacrifice for an important cause. We are forever grateful for their service and sacrifice."
The roadside bomb was fashioned from artillery shells wired together. This kind of makeshift bomb is what the military calls an "improvised explosive device."
U.S. commanders are concerned the devices are getting more powerful and sophisticated. They're now the most common cause of death for U.S. soldiers in Iraq -- deaths that now stand at more than 2,100.
The rising death toll is fueling growing calls in the U.S. for President George W. Bush to bring the troops home.
But Bush said on 30 November he would not set a timetable for their withdrawal. He said U.S. forces were making significant progress in fighting the insurgency and that he would accept nothing less than "complete victory."
U.S. military also says it has been making gains. On 1 December, a coalition operations officer, Major General Rick Lynch, said a series of operations west of Baghdad had prompted a drop in suicide bombings in November.
But U.S. and Iraqi officials have also said insurgent attacks are likely to increase as the 15 December parliamentary elections approach.
And hours after the military announced the marines' deaths yesterday, there was more grim news. Three other soldiers were killed yesterday in a vehicle accident that occurred near Al-Nasiriyah, south of Baghdad, while another soldier has died of wounds sustained the day before during combat operations in Al-Ramadi, west of the capital. That makes a total of 14 U.S. troops killed in Iraq since the start of December.
Meanwhile, The Arabic television network Al-Jazeera aired a videotape showing four Western hostages -- including an American -- kidnapped in Iraq.The kidnappers threatened to kill the hostages -- all Christian peace activists -- unless all detainees in U.S. and Iraqi detention centers are freed by 8 December.
(with news agencies)
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