Updated

China is targeting current and former U.S. service members as part of an exploitation campaign to "fill gaps" in its military capabilities, a top U.S. general says. 

The complex effort was detailed in an Air Force memo authored by Gen. Charles Q. Brown Jr. and distributed on Friday, an Air Force official confirmed to Fox News. The Chinese military is pushing international firms that do business with the PRC to target and recruit "U.S. and NATO-trained military talent across specialties and career fields." 

"By essentially training the trainer, many of those who accept contracts with these foreign companies are eroding our national security, putting the very safety of their fellow servicemembers and the country at risk," Brown wrote in the memo, which was first reported by the Washington Post. He encouraged service members to safeguard "our national defense information" even after they leave the armed forces.

FBI TRACKS OVER 100 INCIDENTS OF CHINESE NATIONALS POSING AS TOURISTS TO BREACH US MILITARY SITES:REPORT

General Charles Brown Jr.

WASHINGTON - JULY 11: Chairman of the Joint Chiefs of Staff nominee General Charles Brown Jr., prepare to testify during his confirmation hearing in the Senate Armed Services Committee on Tuesday, July 11, 2023. (Bill Clark/CQ-Roll Call, Inc via Getty Images) (Bill Clark/CQ-Roll Call, Inc via Getty Images)

A special agent with the Air Force Office of Special Investigation told the Washington Post that China has attempted to exploit Americans through job offers that can appear innocuous. U.S. pilots and other veterans with a wealth of expertise may be approached directly at defense industry events and offered roles where their expertise is needed. The official cited former aerospace ground equipment maintainers and landing-signals officers as examples — jobs which require specialized knowledge to handle equipment and guide pilots and their aircraft to safety, the report said.

But behind these job offers are private companies that are either controlled by the Chinese government or contract with the Chinese Communist Party, according to officials. These entities seek consultants, advisers and trainers who will share their knowledge on the job and unknowingly feed it directly to the Chinese military. 

BIDEN SAYS HE'S 'DISAPPOINTED' CHINA'S XI REPORTEDLY WILL SKIP UPCOMING G20 SUMMIT IN INDIA

Chinese military

New recruits of Chinese People's Liberation Army (PLA) attend a send-off ceremony at a railway station in Ganzhou, Jiangxi province, China March 16, 2023.  (China Daily via REUTERS )

U.S. officials are concerned that service members may be hesitant to leave their jobs even after they discover the connection to China.

"We want to make sure that people understand: If it looks too good to be true, it probably is," the official told the Washington Post. They called the exploitation campaign "insidious."

READ THE AIR FORCE MEMO BELOW. APP USERS: CLICK HERE

The warning comes days after the FBI and Department of Defense reportedly tracked more than 100 incidents of Chinese nationals posing as tourists to attempt to breach U.S. military bases and other federal sites. 

CHINA MOBILIZES COUNTRY TO LOOK OUT FOR FOREIGN SPIES, OFFERS BIG CASH REWARDS

Chinese President Xi Jinping sitting at a session.

Chinese President Xi Jinping discussing the country's economic and social development at a political gathering in Beijing, China. (Lintao Zhang/Getty Images)

Those responsible, dubbed "gate crashers," range from Chinese nationals detected crossing into a U.S. missile range in New Mexico, to scuba divers caught swimming in murky waters near a U.S. government rocket launch site in Florida, several U.S. officials recently told The Wall Street Journal. The growing trend represents a potential espionage threat, as authorities believe the Chinese government in some cases is compelling nationals into service in order to test out and report back about security practices at the installations. 

The FBI has said China poses "the greatest long-term counterintelligence threat to our nation's information and intellectual property." 

CLICK HERE TO GET THE FOX NEWS APP

"The Chinese government is engaged in a broad, diverse campaign of theft and malign influence without regard to laws or international norms that the FBI will not tolerate," an FBI spokesperson told Fox News Digital. "In coordination with our defense and intelligence community partners, along with state and local law enforcement, the FBI is committed to protecting our national security and defense information from the Chinese government's actions and ultimately, their efforts to undermine our democracy and those who defend it."

Fox News' Danielle Wallace contributed to this report.