"Is it likely we will lose somebody else? Yes, it is," said Capt. Thomas H. Johnson Jr., who leads one of the coalition's most battle-scarred units, based in Baghdad. "But all we can do is be as ready as possible."

Johnson's 3rd Brigade soldiers, more than any others in the U.S. 1st Infantry Division, know all about being prepared for battle; their casualty rate is above 25 percent, including six deaths since April.

The death toll of U.S. troops killed in Iraq since the war began last year reached 900 early Wednesday when another 1st Infantry Division soldier was killed. His Bradley fighting vehicle struck a roadside bomb in Duluiyah, 45 miles north of Baghdad.

His death followed those of two Marines and two soldiers, announced Tuesday by the military.

North of Baghdad, Baqouba has turned into one of the coalition's most violent battlegrounds since the U.S.-led invasion in March 2003. It was the city where many of Johnson's soldiers – with an estimated average age of 20 years – learned the art of war and experienced its deadly consequences.

His forces took part in three days of fierce fighting there last month. Black-clad insurgents, firing machine guns and rocket-propelled grenade launchers, shot their way into a government office complex, seized two police stations and destroyed the home of the provincial police chief. The U.S. military said its forces killed 60 guerrillas and lost two of their own.

Associated Press U.S. Army 1st Infantry Division, 3rd Brigade Capt. Thomas Johnson of Atlanta, Ga., discusses soldiers killed in action during an interview in his quarters at Camp Warhorse, in Baqouba, Iraq.

"After last month's clashes and Eckhart's death, you could see in the soldiers' eyes that everybody was physically shattered and they were starting to wonder if they were going to be next and is it all worth it," said 36-year-old Loy, of Ann Arbor, Mich.

"But you can't think about bullets or look at those who died and think, 'I'm next.'"

One of Eckhart's friends, Pvt. Akio Ellis, said fear and anger ran through him after Eckhart was killed.

"It also made me more determined to make this Iraqi government work to make sure my friend didn't die for nothing," said the 22-year-old from Cleveland, Ohio. "And knowing it can happen to me has made me call home more often to tell my parents that I love them."

Johnson says he doesn't dwell on the possibility he might be killed, believing that "this endeavor (in Iraq) is worth our lives."

But he was left distraught after dealing with the consequences of his comrades' deaths, particularly that of his friend 1st Lt. Christopher Kenny, who died in May with three other soldiers when their Humvee rolled into a canal.

"I gave him CPR and mouth-to-mouth, felt a pulse and was with him on the way to hospital, where he died," said Johnson during an interview in his quarters, an air conditioned portable cabin on a dusty military base on a searing summer's day.

"And all I was thinking about was how I was going to tell his wife," he said. "It is the families who suffer most."