NEW YORK — The famed Navajo Code Talkers, the elite Marine unit whose unbreakable code stymied the Japanese in World War II, fear their legacy will die with them.

Only about 50 of the 400 Code Talkers are believed to be still alive, most living in the Navajo Nation reservation that spans Arizona, New Mexico and Utah. Many are frail or ill, with little time left to tell the world about their wartime contribution.

But on Tuesday, 13 of the Code Talkers, some using canes, a few in wheelchairs, arrived in New York City to participate for the first time in the nation's largest Veterans Day parade, set for Wednesday.

The young Navajo Marines, using secret Navajo language-encrypted military terms, helped the U.S. prevail at Iwo Jima and other World War II Pacific battles, serving in every Marine assault in the South Pacific between 1942 and 1945. Military commanders said the code, transmitted verbally by radio, helped save countless American lives and bring a speedier end to the war in the Pacific theater.

They were sworn to secrecy about their code, so complex that even other Navajo Marines couldn't decipher it. Used to transmit secret tactical messages via radio or telephone, the code remained unbroken and classified for decades because of its potential postwar use.

"We were never told that our code was never decoded" or given identities of the original 29 Navajos who created it, said Keith Little, 85, who joined the Marines at 17 and remembers crouching in a bomb crater amid heavy fire on Iwo Jima.

"It was all covered by secrecy. We were constantly told not to talk about it," Little said. The Code Talkers felt compelled to honor their secrecy orders, even after the code was declassified in 1968.

The oldest of the 13 living Code Talkers is 92, and the group includes one of the original 29. Many Code Talkers who served in the war were young farmers and sheepherders who had never been away from home.

"The code did a lot of damage to the enemy," said Samuel Tom Holiday, 85, of Kayenta, Ariz., who also is joining the parade. He was a 20-year-old Code Talker when he and two other Marines went behind enemy lines on Iwo Jima to locate a Japanese artillery unit advancing on American forces.

Once the unit was located, Holiday transmitted a coded message to Marine artillery, which fired a big shell at the Japanese. After the Marine rifleman proclaimed it "right on target," Holiday messaged "Right on Target" to a Navajo Code Talker in Marine artillery.

Though the Code Talkers transmitted information on tactics and troop movements, orders and other vital battlefield communications, they did not know at the time how those messages figured in the greater battle strategy.