Chinese spies have stolen key designs for the F-35 stealth fighter, according to documents disclosed by former U.S. intelligence contractor Edward Snowden, the Sydney Morning Herald reported Monday.

The report, citing disclosures published by German magazine Der Spiegel, said Chinese cyberspies stole huge volumes of sensitive military information, including "many terabytes of data" about the fighter, such as details of the radar systems it uses to identify and track targets.

The allegation was contained in a top secret U.S. National Security Agency presentation apparently obtained by Snowden.