INTERPOL's analysis of trends in terrorism suggests that terrorists continuously increase the sophistication of their tactics to circumvent prevention efforts. Preventive efforts must address this progression in terrorism's sophistication. INTERPOL analysis indicates that 50-60 percent of terrorist crimes involve bombings or explosive devices. This indicates the need to develop explosive detection and screening capabilities. Another aspect of the terrorist problem is the possible use of surrogates, whereby States conduct terrorist operations. This suggests that those actually responsible for a terrorist incident may be different from those who claim responsibility. INTERPOL reports the existence of a significant infrastructure for terrorist groups, which permits participating groups to draw upon a reservoir of resources. INTERPOL's assumption is that the widespread dissemination of information useful to law enforcement in combatting terrorism in various countries can be useful in the international arena.