Former U.S. spy agency contractor Edward Snowden broke his silence on Monday (July 1) for the first time since fleeing to Moscow to say he remains free to make new disclosures about U.S. spying activity.

In a letter to Ecuador, Snowden said the United States was illegally persecuting him for revealing its electronic surveillance programme, PRISM, but made it clear he did not intend to be muzzled.

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

"No matter how many more days my life contains, I remain dedicated to the fight for justice in this unequal world. If any of those days ahead realise a contribution to the common good, the world will have the principles of Ecuador to thank."

Snowden's intervention came after he had applied for political asylum in Russia. President Vladimir Putin had earlier said he was not welcome unless he stopped harming U.S. interests.

Believed to be holed up in the transit area of Moscow's Sheremetyevo airport, Snowden poured scorn on the U.S. government.

"While the public has cried out support of my shining a light on this secret system of injustice, the Government of the United States of America responded with an extrajudicial man-hunt costing me my family, my freedom to travel, and my right to live peacefully without fear of illegal aggression," he wrote in the letter to Ecuador.

Putin, speaking eight days after Snowden landed in Moscow, repeated that Russia had no intention of handing him over to the United States, where he faces espionage charges.

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