He has some advice for Edward Snowden, who recently leaked information about the extent of U.S. electronic surveillance programs.
"I would strongly advise him to go to Latin America," Assange told CNN's AC360 Monday night. "Latin America has shown in the past 10 years that it is really pushing forward in human rights. There's a long tradition of asylum."
Assange spoke from the Ecuadorian Embassy in London, where he has been holed up for almost a year.
Ecuador's government granted him asylum in August, but British authorities have said they will arrest him if he leaves the premises.
Assange had kind words for Snowden, whom he described as heroic, and harsh words for the programs he helped to expose.
Snowden, 29, told the British newspaper the Guardian that he left behind his family and a six-figure job in Hawaii to reveal the extent of the NSA's collection of telephone and Internet data, which he called "an existential threat to democracy."
He worked for computer consultant Booz Allen Hamilton, a contractor for the U.S. electronic intelligence agency.
Snowden took off for Hong Kong before the stories were published and had been holed up in a hotel there, the Guardian reported.
He checked out of his hotel Monday but remains in the semiautonomous Chinese territory, said Ewen MacAskill, the Guardian's Washington bureau chief.
"The oversight of this process is done in secret. The policy is secret," Assange said.
"It's not a case of looking at a particular suspect and deciding to apply surveillance to them as we once did in the past, but rather, just bulk, arbitrary, driftnet fishing across, not just Americans, but essentially the whole of the human race."
In some cases, where there is sufficient evidence, it is right to watch some people for some amount of time, Assange said.
But, he argued, there is no justification for keeping such programs a secret.
"No one accepted and gave (U.S. President Barack) Obama the mandate to engage in a worldwide surveillance program on nearly every person."
Assange fled to the Ecuadorian Embassy in June 2012 to avoid extradition to Sweden, where he is wanted for questioning over allegations that he raped one woman and sexually molested another.
He has said he fears Sweden will transfer him to the United States, where he could face the death penalty for the work of WikiLeaks if he were charged and convicted of a crime.
He has repeatedly said the allegations in Sweden are politically motivated and tied to the work of his website, which facilitates the publication of secret documents.
Assange has not been charged in the United States, though Assange and his supporters say a U.S. grand jury has been empanelled to consider charges against him.
CNN's Matt Smith and Michael Pearson contributed to this report.
Watch Anderson Cooper 360° weeknights 8pm ET. For the latest from AC360° click here.