Global proliferation of ballistic missiles and related technology during the 1970s was a source of extreme unease to the United States. Rather than single-handedly facing this challenge, the United States actively sought the establishment of a multilateral organization to stem the phenomenon. After a series of meetings on the issue from 1983 to 1987 between the United States, Britain, Canada, France, Italy, West Germany and Japan, all seven nations announced, on 16 April 1987, the formation of the Missile Technology Control Regime (MTCR), the first international mechanism controlling proliferation of missiles and related technology. The core limitation imposed by the MTCR is on proliferation of high propulsion ballistic missiles and related technology. It strictly limits the export of missiles capable of delivering a 500 kg payload at a 300-km distance, otherwise known as 500 kg/300 km standard missiles. Components and technology relating to these missiles fall into two categories: Category I items comprise components and technology for express use in high propulsion ballistic missiles; Category II items comprise dual-use components and technology applicable to such missiles. The MTCR imposes strict limits on exports of Category I missiles, components, technology and production equipment, and exerts particularly stringent restrictions on transfers of complete 500 kg/300 km standard missile systems. More flexible regulations apply to Category II exports. The MTCR permits their export on confirmation of their final end-use, or the guarantee that such missiles, components and technology are not used in the construction of high propulsion ballistic missiles.