Since World War II, Portugal has maintained a significant level of defense cooperation with several NATO countries, but its military relations with the United States have been of paramount importance. The United States was granted facilities at Lajes Air Base on Terceira Island in the Azores in 1944. Under a 1951 bilateral defense agreement and subsequent technical agreements, the United States has continued to enjoy access to this base. Lajes has been an important refueling stop for military transport aircraft and a base for tanker aircraft to refuel fighter aircraft shuttling between the United States and Europe and the Middle East. It has also been a base for American antisubmarine aircraft that patrolled a large sector of the sealanes linking the United States Sixth Fleet in the Mediterranean with its supply depots on the east coast of the United States. As of early 1992, the United States had about 1,200 air force personnel in the Azores.

The use of the Lajes Air Base for non-NATO purposes required prior clearance by Portugal. When Israel was subjected to a surprise attack by Egypt and Syria in October 1973, the Lajes Air Base was used to support the emergency transport of military supplies to Israel. Portugal was the only NATO country to grant the United States the use of its facilities during the 1973 crisis. When UN forces were deployed in 1990 in response to the Iraqi occupation of Kuwait, Portugal gave early and comprehensive approval to use Lajes and mainland bases for aerial refueling and moving United States aircraft and equipment to Saudi Arabia.

The 1951 Azores agreement was extended in late 1983 to permit the United States to have continued use of Lajes for seven years until February 1991. As of early 1992, no firm settlement had been reached to extend the agreement. As part of the 1983 understandings, the United States pledged its best efforts to bring its military aid up to an annual level of US$125 million. Assistance totaling US$90 million was provided in fiscal year (FY) 1984 and US$105 million in FY 1985 but, owing to Congressional reductions in the administration's requests, was lower in subsequent years. Estimated military assistance obligations in FY 1990 were US$84.6 million. Disappointment expressed by the Portuguese prime minister with the level of military aid under the 1983 agreement led to consultations in 1988. As a result, the United States agreed to supply additional weaponry to help Portugal bring its NATO-committed forces to a more active posture. Portugal's air defense capabilities were also to be strengthened by introducing interceptor aircraft and modernizing the A-7 squadrons. Among the additional items of equipment the United States committed itself to supply were twenty F-16 fighter aircraft, fifty-seven helicopters of various types, a battery of Hawk SAMs, air defense radar, vehicles, ammunition, and a hydrographic vessel. The previous delivery of P-3 maritime patrol aircraft and the United States contribution to the MEKO frigate program were aimed at augmenting Portugal's antisubmarine warfare capabilit9b3 ity in the Atlantic.

The United States also provided training assistance valued at about US$2.5 million annually. This aid enabled more than 500 Portuguese personnel to receive professional military education each year, as well as training in the effective use and maintenance of weapons systems being delivered under the aid program.

The Federal Republic of Germany (West Germany) had also been a substantial supplier of arms to Portugal, transferring excess Fiat G-91 aircraft, M-48A5 tanks, trucks, and other vehicles. In 1986 West Germany announced that about US$200 million would be earmarked for the construction of the three MEKO-200 frigates. The West German air force maintained eighteen Alpha Jets at Beja Air Base for advanced training of its personnel under an agreement dating from 1960. Both the United States and West Germany used the aircraft repair and overhaul facilities at Alverca under contract with the Portuguese air force. Several other NATO countries have contributed modestly to meet Portugal's military needs, including components for the MEKO frigates. France operated a missile-tracking station on Ilha das Flores in the Azores. In partial compensation, France provided Epsilon training aircraft to the Portuguese air force in 1989.

According to data compiled by the ACDA, the value of arms transfers to Portugal amounted to US$370 million between 1984 and 1988. Of this total, US$210 million originated in the United States, US$30 million in West Germany, and US$20 million in France. The remaining US$100 million came from a variety of suppliers.

Data as of January 1993