A former Central Intelligence Agency (CIA) officer targeted in an FBI undercover operation pleaded guilty on Friday to providing national defence information to China, the US Justice Department said, CNN reported.

Alexander Yuk Ching Ma (71) of Honolulu, who served as a CIA officer for more than seven years in the 1980s, worked with an unnamed co-conspirator in 2001 to provide Chinese intelligence "with a large volume of classified US national defense information" in exchange for tens of thousands of dollars, the US Department of Justice said, citing the plea agreement, CNN reported.