Tehran has tried to build a self-sufficient military program since 1992, manufacturing its own tanks, armored personnel carriers, missiles, radars, boats, submarines, and fighter jets. More recently, Iran's military leaders have said they believe future wars will be air- and sea-based and Tehran has sought to upgrade its air defense systems and naval power in anticipation of such a possibility.
Iran regularly holds military exercises aimed at boosting its defense capabilities and testing new equipment. Tehran also occasionally announces additions to its arsenal, holds inauguration ceremonies, starts up new production lines and test-fires new missiles.
Iran's purported military advancements are impossible to independently verify because the country does not release technical details of its arsenals or rely on equipment from major international defense contractors.