US vs Iran
During this process, we encountered threats, some of which have internal structural roots, and some of which originate from regional and international influence. In order to cope effectively with these types of threats, Iran's defence structure and defence future are based on a foundation of 'strategic deterrent defence.' This [strategy] does not in any way contradict the patterns of reliance on diplomatic relations, but must be understood as 'complementary programs' in a process of creating bilateral and multilateral links [among its various elements]." "Deterrent defence means that in no way will Iran take an offensive measure. We are in struggle to sustain the enemy's first strike. The first strike will not lead to surrender, but it should be seen as a warning. Under these conditions, if there is the [capability] to sustain a first strike, there is a basis for [Iranian] secondary resistance against the threats. Thus, Iran's objectives are of a defensive nature….. Due to the need for 'self-reliance,' a basis for the production of armaments made by the Iranian defence [industry] was created. [This is because] classical weapons alone cannot fully meet the state's defence needs. Some of the research and development by Iran's defence industry is important, because through it, defence needs can be guaranteed."
In early 1999, the acting commander of the ground forces announced that Iran is now producing 14,000 various kinds of aircraft parts. The domestic manufacture of spare military parts has saved the equivalent of 30 billion rials in hard currency. Iran is also producing the clear majority of parts needed by its armed forces, an Iranian armed forces official announced in early 1997. This year, the army’s aviation wing will produce 90 percent of its spare parts requirements. In 1999, Iran’s Minister of Defence stated that Iran’s defence industrial base is now capable of producing the “fundamental hardware” needed by Iran. 
Dr. Abbas Bakhtiar