"Political Violence Against Americans, formerly Significant Incidents of Political Violence Against Americans, is produced by the Bureau of Diplomatic Securitys Office of Intelligence and Threat Analysis (DS/DSS/ITA) to provide readers with a comprehensive picture of the broad spectrum of political violence that American citizens and interests have encountered abroad on an annual basis. This publication encompasses major anti-U.S. incidents; however, some incidents have been omitted due to the sensitive information associated with them. Incidents for this study were selected based upon lethality, substantial property damage, use of unusual tactics or weapons, and perceptibility of targets as U.S. or representative of U.S. interests."
U.S. Department of State: http://www.state.gov/