In several instances, officials of U.S. agencies expressed concerns about shifting resources from the transit zone. In mid-I994, the Drug Enforcement Administration’s Attache in Mexico cautioned that the primary drug interdiction initiative in Mexico--known as the Northern Border Response Force--had been jeopardized by the loss of detection and monitoring coverage in the transit zone. In addition, a senior officer at the U.S. Atlantic Command, which has primary responsibility for detection and monitoring activities in the transit zone, told us that he sees a need to continue detection, monitoring, and interdiction efforts in the transit zone and believes that shifting resources to the source countries would adversely affect this coverage. The Interdiction Coordinator supports the shift in emphasis to source countries but has also cautioned against reducing funding and programs for transit zone interdiction before the United States has an active implementation plan for the source countries.