The Chinese government has built up the world’s largest known online disinformation operation and is using it to harass US residents, politicians, and businesses—at times threatening its targets with violence, a CNN review of court documents and public disclosures by social media companies has found.

The onslaught of attacks – often of a vile and deeply personal nature – is part of a well-organized, increasingly brazen Chinese government intimidation campaign targeting people in the United States, documents show.

The US State Department says the tactics are part of a broader multi-billion-dollar effort to shape the world’s information environment and silence critics of Beijing that has expanded under President Xi Jinping. On Wednesday, President Biden is due to meet Xi at a summit in San Francisco.

Victims face a barrage of tens of thousands of social media posts that call them traitors, dogs, and racist and homophobic slurs. They say it’s all part of an effort to drive them into a state of constant fear and paranoia.