The influence of the United States on the National Guard was overwhelming for many years. Between 1950 and 1976, when military relations were cut off, the total value of United States military aid was US$18.2 million. In addition, some 5,400 members of the guard received training in the United States. After the loss of United States aid, the National Guard managed to obtain some equipment and training assistance from Israel during the final years of the Somoza era to compensate for the loss.

Cuba had the predominant influence on the FSLN during the period before July 1979. Advice, training, money, and moral support were provided, as were some Soviet-made weapons. Captured National Guard weapons were at first used to arm the FSLN guerrillas, but as the struggle to overthrow Somoza escalated in the late 1970s, purchases on the international arms market reached the Sandinistas through Panamanian ports, transiting Costa Rica, which acquiesced in arms transshipment.

In addition to Panama and Costa Rica, Venezuela and other nations of the Andean Pact aided the anti-Somoza effort in the late 1970s in a variety of ways. A Simón Bolívar Brigade, formed in Colombia but also including sympathizers from a number of countries, participated in limited combat alongside the FSLN. Although both the Nicaraguan and Cuban governments downplayed the level of Cuban influence, the Cuban role was clearly paramount.

FSLN leaders requested military aid from the United States in mid-1979, but it was uncertain how serious their request was because they had already accepted Cuban military advisers. Although the request for military aid was rejected, the United States did offer to provide some training in the United States and to supply advisers, instructors, and some assistance in noncombat areas. All of these offers were refused by the Sandinista leaders. The United States administration criticized France for proceeding with a sale of US$15.8 million in equipment--consisting mainly of two patrol boats, two helicopters, trucks, and rocket launchers. As a result of the United States stance, no further military equipment was transferred from Western suppliers.

In March 1980, a high-level delegation that included Minister of Defense Humberto Ortega traveled to Moscow and signed a variety of agreements. Both Nicaraguan and Soviet officials hotly denied that these accords included secret military agreements. The FSLN leaders also visited Bulgaria and the German Democratic Republic (East Germany) both countries subsequently provided military advisers, and some Nicaraguan pilots were trained in Bulgaria.

Deliveries of Soviet weapons began soon after the visit to Moscow. They included the T-55 heavy tank mounted with a 100mm gun, which was an older model of tank with capabilities that were limited under Nicaraguan conditions. Heavy artillery and multiple rocket launchers appeared, far surpassing in range and firepower all other artillery in the region. APCs, jeep-like vehicles, trucks, tanker trucks, and mobile workshops followed to add mobility to the EPS. Soviet helicopters supplied to 13d7 the Nicaraguan air force gave the EPS the means to respond more rapidly to attacks and raids by the Nicaraguan resistance.

Criticizing the Soviet-assisted buildup of the EPS, United States officials underscored the threat of Nicaragua's growing military potential to its neighbors. Other observers regarded the newly acquired weaponry as essentially defensive, adding little to Nicaragua's capacity to wage war beyond its borders. The United States Department of State estimated that the Soviet Union and its allies delivered some 120,000 tons of military and military-related equipment, valued at US$3.3 billion between 1980 and 1990. In most cases, deliveries consisted of older equipment provided at discounted prices under generous terms or as donations.

Prior to July 1979, Panamanian ties with the FSLN were strong, and Panama's support of the Sandinistas included volunteers in a Panamanian brigade that fought alongside the Sandinistas. A group of Panamanian National Guard officers arrived in Managua in late 1979 to offer advisory services, but found that Cubans had already arrived to become the key advisers to the EPS and security organs. Venezuela briefly considered providing training for the nascent Sandinista air force, but declined because of the strong Cuban presence. The United States claimed that as many as 3,500 Cuban military and security advisers were serving in Nicaragua by late 1985, although other sources said there were far fewer. Cuban officers were present during combat operations and served as pilots in some cases, but Nicaragua denied that they actively participated in the fighting. Of thousands of Soviet and Eastern European personnel in Nicaragua, only about thirty to forty Soviet citizens, fifty to sixty East Germans, and a few Bulgarians served with the Nicaraguan military, mostly to provide training in the use and maintenance of Soviet equipment.

The impact of the lessons of the Sandinista success and the subsequent direction taken by the FSLN was considerable, especially in Central America and the Caribbean region. The FSLN victory, in effect, delivered a message to conservative, military-dominated administrations in the area that they could afford to ignore similar groups in their countries only at their own peril. In 1980 and 1981, the FSLN leadership did not hesitate to proclaim Sandinista support for guerrilla movements in Central America, especially in El Salvador, but was circumspect when issues of direct arms and military assistance were raised. In 1981 the United States cut off economic assistance to Nicaragua after publishing an extensive and controversial white paper documenting a flow through Nicaragua of Soviet and Cuban arms to the Salvadoran guerrillas of the Farabundo Martí National Liberation Front (Frente Farabundo Martí de Liberación Nacional-- FMLN). However, FMLN guerrillas were trained by Nicaraguan and Cuban officers in Nicaragua. When the United States stated that Nicaragua's aid to the Salvadoran rebels was the United States motive for supporting the Nicaraguan Resistance, the Nicaraguan government took steps to curtail the outward flow of weapons.

Charges of FSLN support for rebel movements in other Central American nations were not fully substantiated, in spite of repeated reports of Nicaraguan links with Guatemalan and South American insurgent groups. In 1993 the issue of the FSLN's ties with guerrillas and terrorists surfaced again when an arms cache exploded in Managua. The blast revealed tons of weapons, including Soviet surface-to-air missiles, assault rifles, and machine guns, plus ammunition and explosives. Ownership of the weapons was admitted by a faction of the FMLN, which had falsely informed the United Nations (UN) that its weapons had been destroyed in conformity with a UN-mediated peace process. In addition, many documents, including false passports, were discovered, pointing toward a radical faction of Sandinistas continuing to operate clandestinely with ties to left-wing Latin American and European terrorists. A second cache of explosives and light arms appeared soon afterward, linking the Sandinistas to Guatemalan guerrilla groups.

Data as of December 1993