WASHINGTON (Reuters) - The U.S. and other "Five Eyes" countries on Wednesday warned that China has been circumventing measures aimed at halting its recruitment of current and former Western military pilots and other personnel to train the Chinese military.

"Western recruits who train the PLA (Peoples Liberation Army) may increase the risk of future conflict by reducing our deterrence capabilities," said a public bulletin issued by the U.S., British, Canadian, Australian and New Zealand intelligence services.

The notice is the latest warning by the English-speaking "Five Eyes" intelligence-sharing alliance about rising concerns with Chinese government-directed espionage, cyber hacking and intellectual property theft as Beijing's growing might has roiled relations with Washington and its allies.

China's embassy in Washington did not respond immediately to a request for comment.

The PLA is using private companies in South Africa and China to hire former fighter pilots, flight engineers and air operations center personnel from Western countries to train its Air Force and Navy aviators, the services said in the notice.

"The PLA wants the skills and expertise of these individuals to make its own military air operations more capable while gaining insight into Western air tactics, techniques, and procedures," the notice said.

It said the efforts represented a "persistent, adaptive threat," with the insight gleaned by the PLA a threat to "U.S. and allied security."

EXOTIC AIRCRAFT

In one high-profile case, former U.S. Marine pilot Daniel Duggan is fighting extradition from Australia on U.S. charges of training Chinese military pilots through a South African flight school in how to land on aircraft carriers.

Duggan, a naturalized Australian citizen, faces U.S. charges including money laundering and breaking arms control law. He denies the allegations.

Personnel are often contacted through headhunting emails or personal acquaintances from the military, or by privately owned companies with hidden ties to the PLA, the notice said.

The Five Eyes agencies asked people to guard against such offers, which they said often entail promises of lucrative salaries or excessive flattery, and to report any attempts to the FBI or military investigators in their countries.

One official from the U.S. National Counterintelligence and Security Center (NCSC), speaking on condition of anonymity, said the governments issued the warning at this time because China "has been adapting" to countermeasures aimed at thwarting recruitment.

Western pilots have been lured into training Chinese pilots by "tons of money" and opportunities "to fly really exotic" Chinese aircraft, said a U.S. official familiar with the matter.

The official, speaking on condition of anonymity, added that the Chinese military had recruited at least five former pilots from New Zealand and some 30 from Britain, as well as former pilots from Germany and other countries.

The U.S. Commerce Department last year sanctioned more than a dozen companies in China, Kenya, Laos, Malaysia, Singapore, South Africa, Thailand, the U.K, and the United Arab Emirates for their roles in recruiting Western military talent for PLA aviation training.

The U.S. official said the Test Flying Academy of South Africa is "one of the biggest companies" that has been hiring Western former military pilots to train Chinese pilots and has continued doing so despite U.S. sanctions.

The company did not respond immediately to Reuters' request for comment.

In a statement on its website last year, the company said it "does not provide any classified military training, nor train frontline pilots, and all training is based on open-source material or material provided by clients."

It has said it operates with the approval of South African government agencies, does not employ U.S. nationals and had terminated the employment of British nationals following "legal challenges in the U.K. in 2023."

(Reporting by Jonathan Landay, Michael Martina, Katharine Jackson and Ismail Shakil; Editing by Doina Chiacu and David Gregorio)

By Jonathan Landay and Michael Martina