Snowden journalist says leaked documents backed up

American journalist Glenn Greenwald, who helped blow the lid off the United States' secret global spying campaign, said Tuesday he has copies of all the leaked documents the revelations are based on.

No documents were lost after Britain detained his partner, Brazilian-born David Miranda, at London's Heathrow airport on Sunday and confiscated his laptop and other electronic devices, Greenwald told O Globo in an interview.

"We have backups of everything and we will not stop publishing anything, because it is necessary to inform the people about what is happening in the world," said Greenwald, who reports for the Guardian newspaper in Britain.

Greenwald who has published documents leaked by former National Security Agency (NSA) contractor Edward Snowden criticized the detention of Miranda when he flying through London on transit between Germany and Brazil. Miranda arrived Monday in Rio de Janeiro, where he lives with the journalist.

Miranda said in the interview that he was "threatened the entire time" during his hours-long ordeal, adding that his interrogators used "no physical violence," but did apply " psychological violence."

"While it was frightening, I remained calm," he said, adding that one is left "with a lot of fear" after such an incident.

British authorities said they detained Miranda under a terrorism law that allows officials to detain and question suspects at ports of entry, but they did not say what links, if any, they believe he has to terrorist groups.

On Monday, Brazilian Foreign Minister Antonio Patriota called his British counterpart, William Hague, to express his concern.

Miranda, who assists Greenwald in his work, has traveled to Berlin to meet with documentary filmmaker Laura Poitras. While he was in Heathrow's transit area, six agents from Scotland Yard questioned him for nine hours and seized some of his belongings, which they have yet to return.

Snowden, who is wanted by the United States on charges of espionage and stealing sensitive government documents, has been given temporary political asylum in Russia.