The Chinese balloon that traversed the United States before being shot down last weekend captivated public attention and drew sharp denunciations as a brazen spying effort.

But if the vehicle for espionage seemed novel, the concept was anything but.

In ways that are far less public, but often more worrisome, U.S. officials say, the Chinese government has been targeting U.S. industry and government agencies with spy operations designed to collect troves of commercial secrets and sensitive personal data - and to generally give the global superpower a competitive edge.

It's been a constant concern for law enforcement and intelligence agencies across administrations.

"There's a long history of spying on each other. There's a dance and a game that both sides do. In this particular instance, maybe the Chinese got their hands caught in the cookie jar," said Bonnie Glaser, an Asia expert and managing director of the German Marshall Fund's Indo-Pacific program.

China's not the only country the U.S. is concerned about, of course, but its efforts to penetrate American networks often seem more covert than noisy - in contrast, say, to the Russian hack-and-dump of Democratic emails before the 2016 presidential election. And its use of cyber spying to steal industry trade secrets, U.S. officials say, runs afoul of traditional espionage norms.

A look at past Chinese operations:

Cybersecurity Concerns

FBI Director Christopher Wray has repeatedly said the Chinese government has a larger hacking program than all other countries combined, used to steal personal and corporate data and lucrative source code.

China's government, Wray said in a speech last year, "has the global reach and presence you'd expect of the leadership of a great nation, but it refuses to act the part and too often uses its capabilities to steal and threaten, rather than to cooperate and build." He said in a separate address in London last summer that the Chinese government "poses the biggest long-term threat to our economic and national security."

The threat was laid bare in 2014 when the Justice Department, in a first-of-its-kind prosecution, charged five Chinese military officials with hacking into private sector companies in an effort to steal trade secrets.

The following year, Chinese hackers accessed personal information on millions of federal government workers in a hack of the Office of Personnel Management. Subsequent Justice Department indictments have charged Chinese hackers with stealing information from health care insurer Anthem Inc., and with breaking into the computer networks of the Equifax credit reporting agency and obtaining the personal data of tens of millions of Americans.

Other Espionage Operations

U.S. officials have also disrupted other operations on U.S. soil that took place in person rather than behind a computer.

A former Chicago graduate student was sentenced to eight years in prison last month for spying for the Chinese government by gathering information on scientists and engineers in the U.S. with knowledge of aerospace and satellite technology.

The Justice Department has also alleged a more threatening type of physical surveillance, charging eight people in 2020 with working on behalf of the Chinese government in a pressure campaign aimed at coercing a New Jersey man who was wanted by Beijing into returning to China to face charges.

Technology Concerns

The U.S. has long warily regarded China-based companies suspected of having the potential to improperly access user data.

U.S. officials are in private talks about the fate of TikTok, the hugely popular video app that is owned by Beijing-based ByteDance. Wray in December raised national security alarms about the company, saying China could use the app to collect data on its users and has the ability to control the app's recommendation algorithm. TikTok says it has been working to assuage those concerns.

And the U.S. for years has taken action against Chinese tech giant Huawei, alleging that it has the capacity to facilitate spying - a claim the company vigorously denies. Last month, the Biden administration stopped approving renewal of licenses to some U.S. companies that have been selling essential components to the Chinese company.

What China Has Said

When it comes to the balloon itself, China has called it a civilian aircraft used for meteorological research that posed no threat and entered U.S. airspace accidentally.

More broadly, the Chinese Embassy in Washington has repeatedly accused the U.S. of making what it says are baseless and malicious attacks, and has said the U.S. has carried out the same type of hacking operations that it accuses Beijing of doing.

Of course, not all U.S. investigations centered on China have proven successful.

The Trump administration in 2018 developed a program known as the "China Initiative" aimed at cracking down on espionage operations, but it was rebranded last year following a monthslong review in response to complaints that the program chilled academic collaboration and contributed to anti-Asian bias. Several criminal cases against professors in the U.S. who had been accused of concealing research from China have also faltered.

From The Associated Press