A report released Tuesday by an American computer security firm suggests that major, recent cyberattacks against the United States are the work of a Chinese military unit.

Such an allegation isn't entirely shocking; voices ranging from the higher echelons of government to corporate boardrooms of Fortune 500 companies have publicly worried about the growing number of cybercrimes originating in China. What's notable about the study from Mandiant Corp. is its breadth and detail, and amounts to the most damning evidence to date that the People's Liberation Army is behind a massive of cyberespionage campaign that targets foreign governments and companies.

The report says that the attacks -- aiming at everything from defense contractors to Coca-Cola to companies that manage municipal power grids -- can be traced to a single neighborhood of Shanghai and a single office building run by Unit 63198, an arm of the PLA. And while Mandiant refrains from saying with absolute certainty that the Chinese military is at the trail's end of the amassed evidence, it's pretty confident when making that assumption:

“Either [the attacks] are coming from inside Unit 61398,” said Kevin Mandia, the founder and chief executive of Mandiant, in an interview last week, “or the people who run the most-controlled, most-monitored Internet networks in the world are clueless about thousands of people generating attacks from this one neighborhood.”

For its part, the Chinese foreign ministry dismissed the report's allegations as "groundless."

Read the whole report here.