JACKSONVILLE, Fla. -- A 22-year-old Navy petty officer from Jacksonville was killed Wednesday in Iraq -- one of 18 Americans to die in the first three days of fierce fighting to drive insurgents from city of Fallujah.

Julian Woods was a corpsman attached to a Marine Corps unit, and he died as he fought beside the men and women he was there to help save.

"When the doorbell rang this morning and I peeked out the door and saw when I seen those two guys standing there in that white uniform, I just lost it, 'cause I didn't want to hear," his mother, Carolyn Woods, said about the Navy officers who came with news that her youngest son had died.

Woods was in the fourth year of a six-year enlistment. He had a 3-year-old daughter, Israel, who is with her mother, also in the Navy, based in Virginia.

Carolyn Woods said she wasn't told how her son died, but she said that when he joined the Navy, they both understood the risks and that it wouldn't always be a peaceful job.

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"On the days he felt he couldn't go on ... I told him 'you're my hero,'" she said Thursday. "He wrote me back and said, 'No Mom, you're my hero. I get my strength from you.'"

Wood's close-knit family gathered at their Westside home to share their grief and memories.

"We got a lot of good memories. That's all I got now are good memories of my brother," O.J. said. "I'm going to miss him a lot."

Woods joined the Navy after graduating from Ed White High School in 2000, following his father and older brother O.J. into the military.

"I think he's a hero. He's my hero," O.J. said. "At least he went for a good reason."

Two south Florida Marines have also died in fighting in or near Fallujah this week.

Lance Cpl. Juan E. Segura, 26, of Homestead, died Tuesday as a result of enemy action in al-Anbar Province, which includes Fallujah, the Pentagon announced. He was a rifleman assigned to 3rd Battalion, 1st Marine Regiment, 1st Marine Division, I Marine Expeditionary Force from Camp Pendleton, Calif.

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Segura's stepfather told WFOR-TV in Miami that Segura was set to come home for Christmas. He said the family was spending Veterans Day in mourning.

"This holiday has new meaning for me," Jose Torres said.

Sgt. Romulo Jimenez, 21, of Miami, died Wednesday in the battle to oust insurgents, during which 18 U.S. soldiers have died since its start Sunday. He had enlisted recently for a second tour of duty.

Romulo Jimenez learned on Veterans Day from his daughter that his only son and namesake died in "They were patrolling, and they got into some combat," Jimenez said. "He got shot, and he didn't make it. That's what I got from the Marines."

In addition to 18 U.S. soldiers and Marines killed in the Fallujah operation by Thursday morning, military spokesmen say that more than 200 soldiers involved in the offensive have been flown to Landstuhl Medical Center in Germany.

Since Monday, 15,000 U.S. and Iraqi troops have been fighting their way through Fallujah, which for months has been a stronghold of the insurgency in Iraq.

Commanders say militant fighters are trying to break through the U.S.-Iraqi cordon surrounding the rebel stronghold. Authorities say insurgents are aiming attacks and mortar fire at bridges and roads out of Fallujah -- rather than targeting U.S. troops.

The military estimates 600 insurgents have been killed.

Woods' family remained strong as they talked about the son, brother, nephew that will never come home.

"I'm not mad, I'm not angry I'm at peace with myself because my brother, he died for a cause," his younger sister, Alexis said.

A Marine from Homestead was also killed in action in Iraq. Lance Cpl. Juan E. Segura, 26, died Tuesday as a result of enemy action in Al Anbar Province, which includes the town of Fallujah, scene of current fierce fighting, the Pentagon announced. He was assigned to 3rd Battalion, 1st Marine Regiment, 1st Marine Division, I Marine Expeditionary Force from Camp Pendleton, Calif.

Segura's stepfather told WFOR-TV that Segura was set to come home for Christmas. He said the family was spending Veterans Day in mourning.

"This holiday has new meaning for me," Jose Torres said.