The US journalist who broke the first stories about the US National Security Agency's (NSA) global spying programme has asked Brazilian senators to grant asylum to NSA leaker Edward Snowden.

Glenn Greenwald spoke on Wednesday to senators investigating reports about US, British and Canadian spying on Latin America's largest nation.

When the senators pushed him to provide the Brazilian government access to the leaked documents at his disposal, Greenwald balked and said there should always be strict separation between governments and journalists.

Greenwald's partner, David Miranda, also appearing before the senators, added that the documents would not be given to the Brazilian government because it would be an "act of treason" that could prevent Greenwald from ever entering the US again.

Greenwald, a journalist for the Guardian newspaper in Britain, is based in Rio de Janeiro. He previously reported in collaboration with Brazilian media that President Dilma Rousseff's communications with aides were intercepted, that the NSA hacked the computer network of state-run oil company Petrobras, and that the NSA scoops up data on billions of emails and telephone calls flowing through Brazil, which is an important hub for trans-Atlantic fibre optic cables.

He told Brazilian senators that if they really want to better understand US surveillance programmes, they should push their government to provide political asylum to Snowden, who received asylum in Russia on August 1.

Snowden's life 'difficult'

Snowden has not spoken publicly and his whereabouts remain secret.

Greenwald, who said he communicates via chat messages with Snowden several times a week, described Snowden's situation in Russia as "difficult".

Greenwald said Snowden could more freely explain the US spying programme if he were in Brazil.

Brazil's foreign ministry has said it would not respond to a previous request for asylum Snowden made to Brazil and other many other nations, meaning it was not granted but also technically not rejected.

Greenwald told the senate committee that the US government uses spying in large part to gain economic advantages.

"We now have several denunciations that show that the spy programme is not about terrorism. It is about increasing the power of the American government," Greenwald told senators, speaking in Portuguese.

"There are many nations saying, 'We're glad to be learning all this information' but almost nobody wants to protect the person responsible for letting the world discover it," Greenwald said, referring to Snowden and revelations based on the documents he leaked.

Greenwald added that if "a government is serious about defending privacy of data and freedom of the press" it would protect Snowden.

Political fallout

Brazilian government officials told Al Jazeera they were seeking to speak directly with Snowden via videoconference, and that they would be contacting Russian officials in that regard.

The fallout over the spy programmes led Rousseff last month to cancel a planned visit to Washington, where she was to be the guest of honor for a state dinner.

In his most recent report, Greenwald said on a Globo network television show on Sunday that Canadian spies targeted Brazil's Mines and Energy Ministry.

The report said the "metadata" of phone calls and emails from and to the Brazilian ministry were targeted by Canada's Communications Security Establishment. Canadian Prime Minister Stephen Harper said this week that he was "very concerned" about the allegations.