China reportedly stole US military technology for its J-20 fighter

​China ​ripped off US military technology to build an advanced high-tech jet fighter, and experts warn that more must be done to protect American weapons information​ and keep Beijing from making such huge developmental leaps​ in the future, according to a report​ Thursday​.

“What we know is that because of the espionage efforts, [China’s] J-20 is more advanced than it otherwise would be, and that’s the important point here,” former Acting Under Secretary of Defense for Policy James Anderson ​told Fox News Digital in an interview.

“They have profited greatly from their thievery over the years,” ​Anderson said. “They’ve put it to good use, and they’ve come up with an advanced fifth-generation fighter​.”​

But he said it’s difficult to determine how the J-20 matches up against the US F-22 Raptor “short of actual combat.”​​

Beijing started development on the J-20 stealth fighter for the People’s Liberation Army Air Force in 2008 with the aim to develop a warplane that would be able to compete with American fighters, the report said. 

The J-20 embarked on its first flight in 2011 and was introduced into service in 2017. 

But reports surfaced as far back as 2015 noting similarities in technology and capability between China’s jet and US planes — and an Associated Press report even pointed out that “some of its technology, it turns out, may well have come from the US itself.”

The emergence of the J-20 fighter jet shows that China is beginning to bridge the technological chasm with the United States because of its ongoing intellectual property theft — a development that is garnering renewed attention amid tense relations between Beijing and Washington. 

Amplifying the concerns is China’s intentions for self-ruled Taiwan, where an invasion could draw the US into a military clash.

Anderson told Fox News Digital that China employs a variety of espionage techniques, ranging from “old-fashioned” and “low-tech” — like using spies and honey traps, as well as bribery to recruit American contractors, university academics and government officials — to more advanced methods like cyber hacking to pilfer critical military information. 

“Unfortunately, they’ve had some success there,” Anderson said, pointing out that Beijing spent “well over a decade” repeatedly pursuing data about the Joint Strike Fighter for use in the design and construction of the J-20.  

“It saves the Chinese time and money. In effect, we end up subsidizing a portion of their research and development budget because they are successfully stealing some of our secrets,” Anderson said. “Ultimately, this puts our men and women at greater risk on the battlefield.”

Matt McInnis, a senior fellow for the Institute for the Study of War’s China program, said the desire to “understand more sophisticated jet engines” in the West has been a substantial component of Chinese espionage.

McInnis told Fox News Digital that China has placed its focus “almost more than anything else” on acquiring jet engine technology after “struggling for decades” to stay on pace with the US. 

“As someone who’s watched China for a long time, that’s always the joke … will the Chinese ever be able to produce their own jet engine?” McInnis said. “So they’ve slowly been able to become more independent in creating jet engines for their more advanced aircraft.”