The Army counter-terrorism instructional series titled "A Military Guide to Terrorism in the Twenty-First Century" now features theories on kidnapping and other asymmetric warfare tactics deployed by terrorists and other militants, Secrecy News reported.

The section of the manual titled "Kidnapping and Terror in the Contemporary Operational Environment" is written for official use only. However, officials at Secrecy News, a Federation of American Scientists project on government secrecy, obtained a copy.

Officials say the theories developed for the new 168-page manual were taken from years of case studies investigating terrorist kidnapping tactics.

"This document promotes an improved understanding of terrorist objectives, motivation, and behaviors in the conduct of kidnapping," the manual says, according to Secrecy News.