FORT CARSON, Colo. (AP) — Four of the nine soldiers killed when their helicopter went down in Iraq last month were memorialized Thursday as modest heroes dedicated to saving lives — American and Iraqi.

"They asked for nothing and in a moment gave everything," Maj. William LaChance, commander of the 571st Medical Company based at Fort Carson, said in a letter read at a service attended by nearly 700 people.

The Jan. 8 crash near Fallujah killed five other U.S. soldiers whom the four-member medical evacuation team was taking for treatment.

Many soldiers, including LaChance, say they believed the helicopter was shot down, despite being marked with a red cross. The Army has not determined the cause of the crash, a Fort Carson spokesman said.