An al Qaeda front group, the Islamic State in Iraq, claimed Sunday that it had captured U.S soldiers in a deadly attack on a U.S. convoy the day before in Sunni area south of Baghdad that is known as the "triangle of death" — a longtime al Qaeda stronghold.
Meanwhile, 4,000 U.S. troops backed by aircraft, intelligence units and Iraqi forces were scouring the farming area around Mahmoudiya and the nearby town of Youssifiyah for the third day, as the military promised to make every effort available to find the missing soldiers.
Lt. Col. Christopher Garver, a U.S. military spokesman in Baghdad, said the military could not verify the claim by the Islamic State of Iraq but "it would not surprise me if ... al Qaeda in Iraq is involved in this because there are similarities to what they've done before."
He pointed out that the terror network also had claimed responsibility for killing two U.S. soldiers whose mutilated bodies were found after they went missing in the same area last year.
Referring to the two soldiers killed last year, former Marines Capt. Nathaniel Fick told CBS' The Early Show co-anchor Harry Smith that a similar situation for the three soldiers currently missing is "unfortunately terribly likely."
Fick added that soldiers in Iraq are rendered "culturally blind" by the shifting alliances among Iraq's insurgent groups. "It's a three-dimensional battlefield and it's the proverbial hall of mirrors," Fick said.
"It's hard to tell who's your ally," he said.
The Islamic State in Iraq offered no proof for its claim on Internet that it was behind the attack Saturday in Mahmoudiya, about 20 miles south of Baghdad, that also killed four U.S. soldiers and an Iraqi translator.
The group said on its Web site that more details would be released soon, CBS News correspondent Mark Strassmann reports.
If the claim proves true, it would mark one of the most brazen attacks by the Islamic State of Iraq, a coalition of eight insurgent groups, including al Qaeda in Iraq.
Late last month, the group named a 10-member "Cabinet" complete with a "war minister," an apparent attempt to present the Sunni coalition as an alternative to the U.S.-backed, Shiite-led administration of Prime Minister Nouri al-Maliki.
On Sunday, U.S. troops surrounded Youssifiyah and told residents over loudspeakers to stay inside, residents said. They then methodically searched the houses, focusing on possible secret chambers under the floors where the soldiers might be hidden, residents said.
The soldiers marked each searched house with a white piece of cloth.
Soldiers also searched cars entering and leaving the town, writing "searched" on the side of each vehicle they had inspected. Several people were arrested, witnesses said.
Early Monday morning, U.S. and Iraqi forces exchanged fire with gunmen near Youssifiyah during the house-to-house search operation for the missing American soldiers, killing two suspected insurgents and injuring four others, a top Iraqi army officer in the area said.
He said the fighting began at about 3:30 a.m. and lasted for about 30 minutes. The officer, who spoke on condition of anonymity due to security concerns, said the coalition's search operation in the region has detained more than 100 suspects.
The U.S. military did not immediate comment on the report.
In Mahmoudiyah, residents complained on Monday that coalition forces had searched through their homes, and AP Television News footage showed on one apartment that appeared to have been ransacked in the search.
One resident also said three residents in the area, including two guards at a local mosque, had been detained by coalition forces, but that could not be immediately confirmed.
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