A Marine color guard presented the parents of Pfc. Francisco A. Martinez Flores with a framed certificate of naturalization for their son, who was assigned to the 1st Tank Battalion, 1st Marine Division from the Marine Corps Air-Ground Combat Center in Twentynine Palms, Calif. About 100 friends and family attended the ceremony at their Duarte home, northeast of Los Angeles.

"He was a hero," said Martinez's young brother, Sammy.

Martinez's mother, Martha, said her son had always wanted to become a U.S. citizen. He was two weeks away from being naturalized when he died in Iraq March 25.

Also killed that day was 20-year-old Marine Lance Cpl. Patrick T. O'Day of Santa Rosa.

Martinez was listed as missing, but his family was told two days later his body had been found.

Martinez joined two other fallen Marines from Southern California who received posthumous citizenship. Cpl. Jose Angel Garibay and Lance Cpl. Jose Gutierrez, both killed in combat in Iraq, were granted certificates of naturalization April 2 in Laguna Niguel. All three men were single.

Philippines-born Marine Gunnery Sgt. Joseph Menusa, 33, of Tracy, was posthumously granted citizenship on April 4, more than a week after he was killed in combat. The Camp Pendleton Marine, and permanent resident who emigrated to the United States when he was 10, left behind a wife.

Citizenship carries no extra financial benefits for a military man's family.

Garibay, 21, of Costa Mesa, died March 23 in Nasiriyah, south of Baghdad. He was a native of Jalisco, Mexico, whose family moved to the United States when he was a baby.

Gutierrez, 22, of Lomita, died March 21 at the port city of Umm Qasr, becoming one of the first casualties of war. When he was 14, Gutierrez crossed into California from his home in Guatemala.

There are about 31,000 foreign nationals serving in the American military. President Bush signed an executive order last year making it easier for survivors to apply for citizenship for fallen soldiers.

Martinez's family moved to California from Guadalajara when he was 3. The eldest of four, he joined the Marines to pursue his goal of going to college to become a stock broker or detective.