A Chinese-owned company has been manufacturing key circuit boards for top secret next generation F-35 fighter jets flown by the U.K. and U.S., broadcaster Sky News reported Friday.

Axar.az reports citing foreign media that, exception PCB, based in Gloucestershire, southwest England, produces the parts. Its Chinese parent, Shenzhen Fastprint, bought the company in 2013.

The Ministry of Defense (MoD) said in a press release that the circuit boards control many of the F-35’s core capabilities, including its engines, lighting, fuel and navigation systems.

When asked about the ownership of the firm, however, the ministry said Exception PCB is an established manufacturer and presents no risks to the fighter jet’s Joint Strike Fighter supply chain.

"Exception PCB produces bare circuit boards, and as a result, there are no risks associated with their product in the F-35 aircraft supply chain," said a spokesperson for the MoD, downplaying the firm’s importance in the program.

Former defense ministers and experts, however, have expressed concern over a Chinese-owned firm operating at the center of such a secretive program and attribute this to possible Chinese espionage and rivalry.

“We have been completely and utterly naive about the role of China, and it is only now that people are beginning to wake up,” Sir Gerald Howarth, a former Conservative defense minister, told Sky News.

The stealth fighter jet is equipped with an array of highly classified technology that includes sensors and weapons systems. Nine countries form part of the multi-billion-pound Joint Strike Fighter program and companies within these countries produce certain parts of the fighter jet.

China has often been accused of trying to steal information on the secretive and highly sensitive program, which is headed by U.S. defense firm Lockheed Martin.