US journalist Glenn Greenwald (right) speaks with partner David Miranda as Greenwald testifies in front of the Brazilian Federal Senate's Parliamentary Inquiry Committee on Oct 9. UESLEI MARCELINO / REUTERS

Glenn Greenwald, the Guardian reporter who broke many of the stories about secret US surveillance programs, said on Tuesday he is leaving the British daily for an unspecified "dream" project.

Greenwald, a citizen of the United States who lives in Brazil, declined to offer details of his plans, saying they were leaked prematurely.

"My partnership with the Guardian has been extremely fruitful and fulfilling: I have high regard for the editors and journalists with whom I worked and am incredibly proud of what we achieved," Greenwald said in a statement e-mailed to BuzzFeed, the online news site.

"The decision to leave was not an easy one, but I was presented with a once-in-a-career dream journalistic opportunity that no journalist could possibly decline."

Greenwald's plans appeared to have been first leaked by BuzzFeed.

Greenwald told BuzzFeed it would be "a very well-funded ... very substantial new media outlet".

"My role, aside from reporting and writing for it, is to create the entire journalism unit from the ground up by recruiting the journalists and editors who share the same journalistic ethos and shaping the whole thing but especially the political journalism part in the image of the journalism I respect most," he was quoted as saying.

BuzzFeed said Greenwald will continue to live in Rio de Janeiro and will bring some staff to Brazil but the new organization's main hubs will be New York, Washington and San Francisco.

BuzzFeed quoted Greenwald as saying the venture will be a large-scale, broadly focused media outlet.

"It's going to have sports and entertainment and features. I'm working on the whole thing but the political journalism unit is my focus," he said.

In his statement, Greenwald said, "Because this news leaked before we were prepared to announce it, I'm not yet able to provide any details of this momentous new venture, but it will be unveiled very shortly."

The Washington Post reported that Greenwald's venture is being backed by eBay founder and philanthropist Pierre Omidyar but gave few other details. The daily quoted a person familiar with the venture.

It was not immediately clear if Omidyar was the only backer or if there were other partners.

Omidyar, who is chairman of the board at eBay Inc but is not involved in day-to-day operations at the company, has numerous philanthropic, business and political interests, mainly through an investment entity called the Omidyar Network.

Forbes pegged the 46-year-old Omidyar's net worth at $8.5 billion.

Among his ventures is Honolulu Civil Beat, a news website covering public affairs in Hawaii. Civil Beat aimed to create a new online journalism model with paid subscriptions and respectful comment threads, though it is unclear how successful it has been.

Omidyar, a French-born Iranian-American, also founded the Democracy Fund to support "social entrepreneurs working to ensure that our political system is responsive to the public", according to its website.

Omidyar's active Twitter account suggests he is very concerned about the government spying programs exposed by Greenwald and former National Security Agency contractor Edward Snowden.

AFP-Reuters