Fugitive US intelligence analyst Edward Snowden has broken his silence for the first time since he fled to Moscow eight days ago to say he remains free to make new disclosures about US spying activity.

In a letter to Ecuador, Snowden said the United States was illegally persecuting him for revealing its electronic surveillance program PRISM. He also thanked Ecuador for helping him get to Russia and for examining his asylum request.

"I remain free and able to publish information that serves the public interest," Snowden said in an undated letter in Spanish sent to President Rafael Correa of Ecuador.

"There are few world leaders who would risk standing for the human rights of an individual against the most powerful government on Earth, and the bravery of Ecuador and its people is an example to the world," he wrote in the letter, obtained by Britain's Press Association.

Insisting that he had full public support, he accused the United States of conducting "an extrajudicial man-hunt costing me my family, my freedom to travel and my right to live peacefully without fear of illegal aggression".

Venezuelan President Nicolas Maduro said on Tuesday during a visit to Moscow that Snowden deserved the "world's protection" for divulging details of Washington's spy program.

"He deserves the world's protection. He has not asked us for it yet. When he does we will give our answer," Maduro said, adding that he would consider an asylum application if Snowden made one after his request for safety in Ecuador.

Snowden, whose passport has been revoked by the US, singled out Fidel Narvaez, the Ecuadorian consul in London, for praise.

Wikileaks founder Julian Assange revealed last week that it had been Narvaez who issued Snowden a refugee travel document, which allowed him to flee Hong Kong eight days ago as Washington pressed for his extradition.

Ecuador, the first country to which Snowden applied for asylum, now said that Snowden was now Moscow's problem.

"Are we responsible for getting him to Ecuador? It's not logical," Correa said on Monday. He said he could not consider the asylum request and that giving Snowden a temporary travel pass to fly to Moscow was "a mistake on our part".

Snowden has been holed up and in legal limbo in Moscow's Sheremetyevo International Airport for more than a week trying to find a safe haven.

Washington wants him extradited to the US so he can be tried for leaking information detailing a vast US Internet and phone surveillance program.

Snowden, in his letter to Correa, denounced the US program as a grave violation of human rights.

"This global system affects every human life touched by technology; recording, analyzing, and passing secret judgment over each member of the international public."

In his letter to Correa, Snowden declared: "No matter how many more days my life contains, I remain dedicated to the fight for justice in this unequal world."

AFP-Reuters