TARGETS

Snowden's claim the NSA is engaged in industrial espionage follows a New York Times report earlier this month that the NSA put software in almost 100,000 computers around the world, allowing it to carry out surveillance on those devices and could provide a digital highway for cyberattacks.

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The NSA planted most of the software after gaining access to computer networks, but has also used a secret technology that allows it entry even to computers not connected to the Internet, the newspaper said, citing US officials, computer experts and documents leaked by Snowden.

The newspaper said the technology had been in use since at least 2008 and relied on a covert channel of radio waves transmitted from tiny circuit boards and USB cards secretly inserted in the computers.

Frequent targets of the programme, code-named Quantum, included units of the Chinese military and industrial targets.

Snowden faces criminal charges after fleeing to Hong Kong and then Russia, where he was granted at least a year's asylum.

He was charged with theft of government property, unauthorised communication of national security information and giving classified intelligence data to an unauthorised person.