DENVER: The journalist behind stories about the National Security Agency's global spy program promised Monday that 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 by video to a group of reporters from around the Americas gathered in Denver for a meeting of the Inter American Press Association. He said the upcoming reports will be as significant as the report he co-wrote in the French newspaper Le Monde about the NSA sweeping up millions of phone records in France in a month.

Greenwald said he's committed to reporting on every document of public interest given to him by former NSA contractor Edward Snowden. He said he does consider the potential harm that could be caused by his disclosures and consults with experienced editors and reporters in deciding what to publish. He also said they present their reporting to the government at issue to listen to officials' view about publishing the information, but he acknowledged they usually disregard it.

''I don't think anyone could say we have not been thoughtful enough,'' he said.

Snowden told Greenwald earlier this year about the vast communications-monitoring programs carried out by the agency and its international counterparts. The revelations have sparked a raucous debate about the scale of surveillance and the erosion of privacy in the digital age.

Snowden received asylum in Russia in August.

Greenwald said there's a ''sustained attack'' on press freedom in the United States, and he criticized the British government for asking the Guardian newspaper to destroy data leaked by Snowden. He called on journalists everywhere to work together to defend their rights.

''The more we band together, the harder it will be for states to attack press freedoms,'' he said.

The Miami-based Inter American Press Association has about 1,400 member news organizations and promotes press freedoms throughout the Americas. Earlier speakers at the general assembly included Associated Press president and CEO Gary Pruitt and Cuban dissident blogger Yoani Sanchez, who spoke about arrests of independent journalists and bloggers there.

Pruitt spoke about the US Justice Department's seizure of records of thousands of telephone calls to and from AP reporters as part of an investigation to find the source of a story about a foiled attempt to bomb a US-bound airliner, a move that Greenwald also criticized during his remarks.