The files indicate that the U.S. National Security Agency accessed the SWIFT interbank messaging system, allowing it to monitor money flows among Middle Eastern and Latin American banks.

The leak of what purports to be a NSA hacking kit has set the information security world atwitter and sent major companies rushing to update their defences.

Hackers say they plan to auction stolen surveillance tools they say were used by a cyber group linked to the U.S. National Security Agency.