The United States indicted 10 Chinese, including two intelligence officers, over a five-year scheme to steal technology from US and French aerospace firms by hacking into their computers.

The indictments came 20 days after the Department of Justice obtained the unprecedented extradition of a senior Chinese intelligence official from Belgium to stand trial in the United States for running the alleged state-sponsored effort to steal US aviation industry secrets.

The Justice Department said the Chinese Ministry of State Security, through its Jiangsu province unit, engineered the effort to steal the technology underlying a turbofan engine used in US and European commercial airliners.

The engine was being developed through a partnership between a French aerospace manufacturer with an office in Suzhou, Jiangsu province, and a US firm, it said.

The companies were not named, but earlier indictments pointed to Cincinnati, Ohio-based GE Aviation, one of the world’s leading aircraft engine manufacturers.

Meanwhile France’s Safran Group, which was working with GE Aviation on engine development, has an office in Suzhou.

The operation first became public in September when the US indicted a Chinese-American engineer for helping steal files at the direction of a top official of the Jiangsu State Security bureau.

Then on October 10 the Justice Department announced it had obtained the extradition of Xu Yanjun, the deputy division director of the Jiangsu bureau, from Belgium where he had apparently been lured and arrested in a counterintelligence operation.

Tuesday’s indictments named the two officials of the Jiangsu security bureau who apparently worked under Xu, six hackers who worked under them, and two men who worked for the French company.

The case has added to rising tensions between Beijing and Washington over geopolitics, trade, hacking and corporate espionage.

After Xu’s arrest, China said the United States was “making something out of thin air.”

The new indictments detailed efforts to use malware and phishing techniques to hack into target computers and remove data on the engines and parts.

“At the time of the intrusions, a Chinese state-owned aerospace company was working to develop a comparable engine for use in commercial aircraft manufactured in China and elsewhere,” the Justice Department said.

“For the third time since only September, the National Security Division, with its US Attorney partners, has brought charges against Chinese intelligence officers from the JSSD and those working at their direction and control for stealing American intellectual property,” said Assistant Attorney General John Demers.

“This is just the beginning. Together with our federal partners, we will redouble our efforts to safeguard America’s ingenuity and investment.”

The FBI worked ont he case together with France’s General Directorate for Internal Security.