Washington, March 11 (RHC)-- The U.S. Central Intelligence Agency (CIA) has made sophisticated efforts for nearly a decade to break the security of Apple's mobile phones and tablets, according to newly published top-secret documents. CIA researchers have worked since 2006 to create surveillance "backdoors" into programs used by Apple's iPhones and iPads, investigative news site The Intercept reported on Tuesday, citing documents obtained from US whistleblower Edward Snowden.

Efforts to break into Apple products by CIA security researchers was part of a top-secret program by the U.S. and British governments to hack "secure communications products, both foreign and domestic" including Google Android phones, according to The Intercept.

"U.S. government-sponsored research has been aimed at discovering ways to decrypt and ultimately penetrate Apple's encrypted firmware. This could enable spies to plant malicious code on Apple devices and seek out potential vulnerabilities in other parts of the iPhone and iPad currently masked by encryption."

Apple and Google say they have strengthened encryption methods to protect the privacy of users of their products and that this was in response to the large-scale spying of Internet users by the National Security Agency (NSA) revealed by Snowden in 2013.