A prominent veteran of the Navajo 'code talkers' who confounded enemy combatants in World War II by using the Navajo language as a battlefield cipher in the South Pacific has died, a veteran's association said.

Keith Little, 87, served in the US Marine Corps 4th Marine Division in the Pacific and was president of the Navajo Code Talkers Association.

He died on Tuesday evening at a medical centre in Fort Defiance, Arizona.

The code talkers used a unique cipher based on the Navajo language to encrypt messages sent by field telephones and radios throughout the Pacific theatre.

It was regarded as secure from Japanese code breakers as the consonant-rich language was only spoken in the US south-west, was known by fewer than 30 non-Navajo people, and had no written form.

Mr Little was a young Navajo shepherd when he enlisted with the Marines at age 17 in 1943.

He trained as a code talker and was sent to the South Pacific where the small band of specialists served in all six Marine divisions and took part in major assaults.

In an interview in 2007, Mr Little told Reuters how he scrambled down a cargo net with his radio pack and rifle, leaping into a landing craft in the roiling ocean off the Marshall Islands in early 1944.

The Navajos sent and received messages as warplanes raced overhead, artillery pounded Japanese positions, and troops fought with fixed bayonets.

The Navajos' reputation grew as island after island fell and was sealed at Iwo Jima, which the Marine Corps took back in a 35-day battle in which nearly 20,000 Japanese and 7,000 Americans died.

In that battle six Navajo code talkers worked around the clock, sending and receiving more than 800 vital messages without error in the first two days of the battle alone.

In his later years as president of the Navajo Code Talkers Association, Mr Little took responsibility for safeguarding the memory of the 420 Navajo code talkers.

He was a driving force behind the National Navajo Code Talkers Museum & Veterans Centre, a project still in development.

"This was no ordinary contribution to America," Mr Little told Reuters.

"The Navajo Code Talkers did something unique, incredible ... and it should be observed."

A public memorial service is being planned.

Reuters