(CNN) Joe Vandever Sr., a member of the top-secret Navajo Code Talker program that developed an unbreakable code language during World War II, has died, according to Navajo Nation President Jonathan Nez.

Vandever was 96; his family says he died from health complications, according to Nez. He died Friday morning in Haystack, New Mexico, Nez said, five days shy of his 97th birthday.

"Joe Vandever, Sr. was a great warrior and a compassionate family man. In every aspect of his life, he was a loving person who cared greatly for his people," Navajo Vice President Myron Lizer said.

Navajo Code Talker Joe Vandever Sr. celebrates the annual Navajo Code Talker Day in Window Rock, Arizona, on August 14, 2019.

Vandever served largely in the Pacific region during his service in the US military. He enlisted with the Marine Corps in Santa Fe, New Mexico, on March 26, 1943, and was honorably discharged as corporal on January 22, 1946.

Vandever was one of hundreds of Navajo tribe members who were trained as code talkers in World War II . Between 375 and 420 Navajos used a secret code language to send information on tactics, troop movements and orders over the radio and telephone during the war. The language was indecipherable to the Japanese and a key factor in American military victories at Iwo Jima, Saipan and several other major battles.

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