The Justice Department announced Monday that it indicted four members of China's military in relation to the 2017 Equifax data breach that compromised the data of more than 147 million Americans.

Why it matters: The announcement comes at a fraught time for U.S.-China relations — just weeks after the signing of a critical "phase one" trade deal that ratcheted down economic tension between the two nations — and marks only the second time that the U.S. government has charged Chinese military hackers.

The hack, which also exposed some of the company's trade secrets, also brings the issue of Chinese government-backed intellectual property theft — a top Trump administration worry — back to the forefront.

It isn't the first massive China-backed corporate hack, as a Marriott data breach that affected as many as 500 million customers as far back as 2014 was tied to Chinese intelligence services in 2018.

The big picture: Attorney General William Barr called the breach, which utilized a security vulnerability in the software for the firm's online dispute portal, a "deliberate and sweeping intrusion into the private information of the American people."

The DOJ said that the hackers "ran approximately 9,000 queries on Equifax’s system, obtaining names, birth dates and Social Security numbers for nearly half of all American citizens."

Read the indictment: