Meanwhile, bloodshed claimed at least 18 lives across Iraq on Sunday, including two U.S. and five Iraqi soldiers killed by bombings in Baghdad. The attacks are part of an increase in violence seen in recent days after a relative lull in attacks around the Dec. 15 parliamentary elections.
Then on Monday, insurgents killed at least 10 people in attacks around Iraq, including five police officers killed at a checkpoint. Attackers exploded five car bombs around Baghdad but caused relatively few casualties.
The U.S. military said both Americans were with Task Force Baghdad. A statement said only that the first soldier "died from wounds sustained by an improvised explosive device." It said the other was killed when his vehicle was hit by a roadside bomb while on patrol in the capital.
In other developments:
U.S. troops woke long before sunrise on a cold, rainy Christmas morning to raid an upscale neighborhood a few miles from their base. In honor of the day, they dubbed the target "Whoville," after the town in the Dr. Seuss book "The Grinch Who Stole Christmas."
Commanders said they ordered the operation because they did not know the identities of the neighborhood's residents and several roadside bombs had recently been planted near the district, which isn't far from Forward Operating Base Summerall in Beiji, 155 miles north of Baghdad,
U.S. patrols had never before ventured into the neighborhood, where the streets are lined with spacious homes.
Soldiers from the 101st Airborne Division's 3rd Brigade knew they weren't going to be welcome when they arrived in the dead of night. It just made sense to nickname the target after the village raided by Seuss' Grinch on Christmas morning, they said.
"It was appropriate. I did feel like the Grinch," said Pfc. John Parkes, 31, of Cortland, New York, a medic in one of several groups called "quick reaction teams" that respond to roadside explosions.
The raiders broke down doors, confiscated illegal machine guns, plastic bags of ammunition and gun clips. Iraqi law allows households to own AK-47s, but with limitations.
For many soldiers, the holidays are more of a benchmark for their time in Iraq than a special day.
"Believe it or not, I didn't realize it was Christmas until last night," said 1st Sgt. Andre Johnson, 38, of Baton Rouge, Lousiana. "It's just another day, man."
Another day on patrol. Another day walking the streets while the cold wind cut through their uniforms and a chilling drizzle coated their faces. The neighborhood's residents stayed inside, peeking through windows at the passing soldiers.
Sgt. Jared Jones, 21, of Lafayette, Indiana, said Christmas away from home can be emotional for some, but he buries himself in his job.
"The mission comes first," he said, pulling heavily on a cigarette after returning to the base. "I was out here 15 months the last time I was in Iraq. Holidays don't matter much to me."
Maj. Alex Lee sees Iraq from a different perspective serving in Balad, a town 50 miles north of Baghdad.
He is a doctor at the largest U.S. military hospital in Iraq, and his early Christmas shift began quickly: Four American soldiers were flown in by helicopter suffering from burns caused by a roadside bombing near the insurgent stronghold of Ramadi.
One soldier arrived with burns on his back. His exposed legs trembled from the cold and he unconsciously tore off an air tube placed down his throat. A sweating medic knelt beside him and told the doctors about his condition.
"This is the most medically rewarding thing I'll ever do," Lee, of Bakersfield, California, said as he stood in the emergency room, its floor speckled with blood. "This is why we joined up."
"Honestly, it doesn't feel like a holiday," he added. "But for the guys that are conscious, we try to say 'Merry Christmas' to them. But it is hard to keep holiday spirits up."
Located on an air base, the hospital is a stretch of interconnected white plastic tents covering more than 35,000 square feet.
For Senior Airman Heather Ross, a medical technician, Christmas involved administering intravenous fluids and cleaning up after patients, mostly Iraqi soldiers wounded during an ambush on Saturday. One of her patients was a 4-year-old boy injured in a mortar attack that killed his two brothers.
"It's not even a holiday here. It doesn't feel like Christmas. My 18-month old daughter is home for the second straight Christmas without me," said Ross, of San Antonio.
During a pause between rounds, she showed e-mails of her daughter to visitors and e-mailed others to family and friends.