Officials said it took well over a year to track them through the 34 servers in 20 countries they allegedly used to hide their tracks.
“This was an organized and remarkably brazen criminal heist of sensitive information of nearly half of all Americans, as well as the hard work and intellectual property of an American company, by a unit of the Chinese military,” Barr said.
The hack stunned US intelligence officials, following a similar intrusion on the civil service database of the Office of Personnel Management (OPM), also blamed on the Chinese.
Since then, as well, hotels giant Marriott lost data on some 500 million global customers to hackers believed to be Chinese.
US officials believe the Chinese military and security service are collecting personal data on Americans for strictly intelligence purposes.
After the OPM hack there were worries that Beijing could use the information to identify US spies working under the cover of non-intelligence jobs.
FBI Deputy Director David Bowdich said there was no evidence yet of the Equifax data having been used, for example to hijack a person’s bank account or credit card.
But he added: “If you get the personal identifying information of people, you can do a lot with that.”
The US believes the suspects are currently in China.