Illicit trafficking in or smuggling of nuclear and other radioactive materials occurs worldwide and has reportedly increased in recent years. According to the International Atomic Energy Agency1 (IAEA), as of December 31, 2001, there had been 151 confirmed cases of illicit trafficking of nuclear material since 1993. (See app. I for more information about nuclear smuggling cases.) A significant number of the cases reported by IAEA involved material that could be used to produce a nuclear weapon or a device that uses conventional explosives with radioactive material ("dirty bomb") to spread radioactive contamination over a wide area. Nuclear material can be smuggled across a country's border through a variety of means: it can be hidden in a car, train, or ship, carried in personal luggage through an airport, or walked across an unprotected border. Many nuclear smuggling cases have been traced to nuclear material that originated in the countries of the former Soviet Union. The United States, through the Department of Energy's Material Protection, Control, and Accounting (MPC & A) program, has helped these countries secure nuclear material at civilian and defense facilities-this effort is considered the first line of defense against potential theft and/or diversion of nuclear materials. To address the threat posed by nuclear smuggling, the United States is helping these countries improve their border security-a second line of defense-but these assistance efforts face daunting challenges3. For example, Russia alone has almost 12,500 miles of borders with 14 countries, including North Korea. It is also in close geographical proximity to Afghanistan, Iran, and Iraq.