The United States has charged four Chinese military hackers in the 2017 breach of the Equifax credit reporting agency that affected nearly 150 million people, Attorney General William Barr says.
"This was a deliberate and sweeping intrusion into the private information of the American people," Mr Barr said in announcing the indictments of four members of the Chinese Liberation Army in connection with one of the largest data breaches in US history.
Roughly 147 million people had information including Social Security numbers, birth dates and driver's licence data compromised by the Equifax breach.
The hackers spent weeks in the Equifax system, breaking into computer networks, stealing company secrets and personal data.
The hackers routed traffic through approximately 34 servers located in nearly 20 countries to obfuscate their true location.
Equifax CEO Mark Begor said the company was grateful for the Justice Department investigation.
"It is reassuring that our federal law enforcement agencies treat cybercrime - especially state-sponsored crime - with the seriousness it deserves," he said in a statement.
Senator Ben Sasse, a Republican member of the Senate Select Committee on Intelligence, urged tougher action to counter Chinese hacking.
"The Chinese Communist Party will leave no stone unturned in its effort to steal and exploit American data. These indictments are good news, but we've got to do more to protect Americans' data from Chinese Communist Party influence operations," he said in a statement.
The Equifax data breach, because it was so large and involved so much sensitive financial information on so many US citizens, had far-reaching implications for Equifax and the consumer credit industry.
The company agreed to pay up to $AU1 billion to settle claims it broke the law during the data breach and to repay harmed consumers.
The scandal sent the company into turmoil, leading to the exit of then-CEO Richard Smith, and multiple congressional hearings as the company's slowness to disclose the breach and security practices were challenged by lawmakers.
