FBI
http://www.fbi.gov/about-us/investigate/terrorism/terrorism
Department of Homeland Security (US)
http://www.dhs.gov/index.shtm
CIA World Factbook
https://www.cia.gov/library/publications/the-world-factbook/
DGSE (France) General Directorate For External Security
http://www.defense.gouv.fr/dgse (website in French)
http://www.fas.org/irp/world/france/defense/dgse/ (site in English)
BND (Germany)
http://www.bnd.bund.de/cln_227/DE/__Home/Startseite/startseite__node.html?__nnn=true