1970, in response to increasing acts of air piracy by hijacking to Cuba and Islamic radicals, President Richard Nixon ordered the immediate deployment of armed federal agents on United States commercial aircraft. Initially, the deployed personnel were federal agents from the U.S. Department of Treasury. Subsequently, the United States Customs Service formed the Division of Air Security, and established the position of Customs Security Officer (CSO). Approximately 1,700 personnel were hired for this position and were trained at the Treasury Air Security Officer (TASOS) training complex at Fort Belvoir, Virginia. Customs security officers were deployed on U.S. flagged commercial aircraft, flying on both domestic and international routes in an undercover capacity in teams of two and three. Customs security officers also handled ground security screening on selected flights at domestic U.S. airports. Following the mandatory passenger screening enacted by the FAA at U.S. airports beginning in 1973, the customs security officer force was disbanded and its personnel were absorbed by the U.S. Customs Service. By 1974 armed sky marshals were a rarity on U.S. aircraft. The former customs security officers were reassigned as customs patrol officers, customs inspectors, and customs special agents. A small force of Federal Air Marshals were retrained at the FAA starting in 1974. The personnel trained under this program was limited to 10–12 people. For the next several years after customs security officer disbandment, the FAA air marshals rarely flew missions. In 1985, President Ronald Reagan requested the expansion of the program and Congress enacted the International Security and Development Cooperation Act, which expanded the statutes that supported the Federal Air Marshal Service. The FAM program was begun in response to domestic hijackings and FAM operational flights were almost exclusively conducted on domestic U.S. flights until 1985. After the hijacking of TWA Flight 847 in 1985 and the enactment of the International Security and Development Cooperation Act, the number of FAMs was increased and their focus became international U.S. air carrier operations. Due to resistance of several countries including the United Kingdom and Germany to having individuals carrying firearms entering their countries, the coverage of international flights was initially limited. Resistance to the entrance of armed personnel to their countries was overcome through negotiations and agreements about the terms and handling of weapons when they were brought in country. Hence the FAMs could operate worldwide in carrying out their mission to protect U.S. aviation from hijackings.