Americans owe US intelligence leaker Edward Snowden a debt of gratitude because he prompted President Barack Obama to promise an overhaul of secret surveillance, whistle-blowing WikiLeaks founder Julian Assange says.

The Bulgarian news agency BGNES and a number of international media reported Sunday that according to Assange, Obama had "validated Edward Snowden's role as a whistleblower" by announcing plans which promised greater oversight and transparency.

"Today was a victory of sorts for Edward Snowden and his many supporters," Australian-born Assange has written Saturday on his Australian website.

"Well reforms are taking shape, and for that, the President and people of the United States and around the world owe Edward Snowden a debt of gratitude."

Edward Snowden, a former intelligence contractor, has admitted leaking information about US surveillance programs to the media.

He fled the US - where he now faces espionage charges - and has been granted temporary asylum in Russia.

Weeks after the leaks, the US President keeps denying abuse and illegal snooping, but recently promised "appropriate reforms" to guarantee greater oversight of controversial US surveillance programs.

At a White House news conference on Friday, he proposed "safeguards against abuse", including amending legislation on the collection of telephone data.

Obama also went on to criticize Russia, which recently granted asylum to Snowden. Earlier in the week, the US President also cancelled a planned summit with President Vladimir Putin next month in Moscow.

"I don't think Mr Snowden was a patriot," Obama said.

Assange insists Snowden made surveillance reforms possible by disclosing the information on surveillance programs in the US.