[imported_Fluffy_Bunny]

FBI-Federal Bureau of Investigation - Federal, US based intelligence agency like MI5.

CIA- Cental Intelligence Agency- foreign affairs based intelligence agency like MI6.

It dosen't take a genius to figure out that a foreign affairs based intelligence agency has to have more power to spy on other countries etc.
The FBI walk around with big FBI letters printed all over their jackets, you can spot them a mile away. Whereas the CIA walk around Mosco in snappy suits and try to look inconspicuous.


Personally I think the KGB has more power