(CNN) Fleming Begaye 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

Begaye was 97.

Begaye served as a Navajo Code Talker in the Marine Corps from 1943 to 1945 and fought in the Battle of Tarawa and the Battle of Tinian, the Great Navajo Nation noted in a statement. He spent one year in a naval hospital for service injuries.

Begaye was born in 1921 in Red Valley, Arizona, and resided in Chinle, Arizona, when he died Friday, the Great Navajo Nation says. His cause of death was not released.

"We offer our heartfelt appreciation to the family for sharing his life with us," Nez said via Twitter on Friday. "May the Creator bless you and your family with strength and comfort."

As a code talker, Begaye was one of a group of Navajos who learned a secret, unbreakable language that was used to send information on tactics, troop movements and orders over the radio and telephone during WWII.

The code was indecipherable to the Japanese and a key factor in American military victories at Iwo Jima, Saipan, and several other major battles.

At Iwo Jima, code talkers passed more than 800 error-free messages in 48 hours, according to the congressional law honoring the program

"Were it not for the Navajos," said Maj. Howard Connor, the signal officer of the Navajos, "the Marines would never have taken Iwo Jima."

President Donald Trump met with Navajo Code Talker Fleming Begaye Sr., seated, in the White House in Washington, DC on Nov. 27, 2017.

Begaye was one of three surviving code talkers who were honored at the White House in November 2017. The event was overshadowed by President Donald Trump's attempt to insult Sen. Elizabeth Warren by calling her Pocahontas.

Prior to that comment, Trump spoke in awe on a topic he admitted he had known little about beforehand.

"I have to say, I said to Gen. (John) Kelly ... I said, 'How good were these code talkers? What was it?' He said, 'Sir, you have no idea. You have no idea how great they were -- what they've done for this country, and the strength and the bravery and the love that they had for the country,'" Trump said, turning to the code talkers, "and that you have for the country."

The Navajo Nation said that less than seven code talkers are still alive of the more than 400 who served.

Arizona Gov. Doug Ducey said the state had lost an "American hero" with Begaye's death.

"Today, Arizona celebrates the life of Mr. Begaye, and we express our gratitude for his service and sacrifice in defense of freedom," Ducey said in a statement. "We express our deepest sympathies to Mr. Begaye's family, friends and the entire Navajo Nation."

How the Navajo Code Talkers came to be

Private First Class Preston Toledo and his cousin, Private First Class Frank Toledo, both Navajos, relay orders over a field radio in their native tongue on July 7, 1943.

The plan to use the Navajo language as a secret code began with Philip Johnston, who had spent his childhood on a Navajo reservation while his parents served as missionaries, according to the CIA

The US military had used the Choctaw language during World War I as part of its secret code. Germany and Japan worked to learn Choctaw and other Native American languages between the wars, the CIA said.

But the Navajo language is particularly tricky for non-Navajo people, and it is not written. The Marines recruited and trained 29 Navajos at Camp Elliott near San Diego beginning in 1942.

Those 29 Navajo created more than 200 new Navajo words for military terms and committed them to memory.

"I studied on my own at night," Joe Hosteen Kellwood, one of the code talkers, said of his training . "You had to memorize all the words at the time, 211 words. They were long words. I spelled it. I learned."

In simulated battles, the Navajo code proved much faster than the encrypting machines being used at the time. So in August 1942, 15 code talkers -- just over half the recruits -- joined the Marines for combat duty amid the assault on Guadalcanal.

After that first battle, Maj. Gen. Alexander Vandegrift, commander of the 1st Marine Division, sent word back to the US asking for more Navajos, according to code talker Peter MacDonald.

"This Navajo code is terrific," Vandegrift said, according to MacDonald. " 'The enemy never understood it,' he said. 'We don't understand it either, but it works. Send us some more Navajos.' "

More than 400 Navajo had learned the code by the end of the war. None of the original 29 code talkers who invented the language are still alive. Chester Nez, the last surviving member of the original 29, died in 2014

The program wasn't declassified by the military until 1968, and it would take several more decades before the story received wider recognition. In 2001, President George W. Bush presented the 29 original Navajo Code Talkers with the Congressional Gold Medal.