Examples of both domestic and international terrorist activities are used to illustrate the extent of the gunrunning problem. Generally, domestic and international terrorist groups obtain their weapons differently. American firearms laws are relatively simple, requiring recordkeeping of arms manufacture, transfer, and sales; licensing of manufacturers, wholesalers, importers, and retailers; prohibiting sales to or purchases by certain persons (such as felons); restricting the types of weapons which may be imported; and registering certain types of weapons (generally heavy arms and explosive devices). Regulations in some foreign countries are strict, forcing terrorist groups to obtain weapons illegally through theft or smuggling. It is difficult to estimate the number of weapons stolen in the United States yearly. Thefts for terrorist purposes are usually from military arsenals, interstate shipments, or arms dealers while thefts from individuals are usually for criminal rather than terrorist purposes. As urban terrorists, most domestic groups focus on handguns; heavier weapons and long-barreled rifles are unsuited to their tactics. Tracers on weapons recovered from terrorist groups in the United States have indicated, however, that most of these weapons were legitimately purchased. Smuggling has not been a highly used method for obtaining weapons to date, but should terrorists desire heavy weapons -strictly controlled in this country -- smuggling is the logical avenue. International terrorist groups probably obtain large numbers of weapons from communist nations as gifts. Weapons smuggled out of the United States are another large supply source. For example, a large, illicit gun smuggling trade which also includes ammunition exists between the United States and Mexico.