Min S. Choi

RIVER VALE, N.J. — A 21-year-old soldier from this Bergen County community was killed Saturday when an explosive device detonated near his patrol in Abertha, Iraq, the Defense Department said Tuesday.

Pfc. Min Soo Choi died just one month after he was deployed, according to family members.

Choi, who was assigned to the 3rd Infantry Division’s 6th Squadron, 8th Cavalry, had moved to River Vale with his family from South Korea about seven years ago.

Although he was not yet an American citizen, he told a neighbor, Donna LoPiccolo, “I’m just proud to serve.” His father, Jung Choi, said his son looked forward to becoming a citizen after completing his military service.

Choi was a 2003 graduate of Pascack Valley High School, where he played golf and soccer. School principal Barbara Sapienza described him as “a very well-respected young man.”

Choi was...