The journalist behind stories about the National Security Agency’s global spy program promises there are many more to come, including details about the United States’ spying on its own citizens.

Glenn Greenwald, an American reporter based in Brazil, spoke Monday by video to a group of reporters from around the Americas gathered in Denver. He said the upcoming reports will be as significant as the report he co-wrote in Le Monde about the NSA sweeping up phone records in France.

Greenwald said he’s committed to reporting on every document of public interest given to him by former NSA contractor Edward Snowden.

He also said there’s a “sustained attack” on press freedom in the United States and called on journalists everywhere to work together to defend their rights.

(AP)