Most of Iran's imported weapons consist of American systems purchased before the 1979 Islamic Revolution, with limited purchases from the Soviet Union in the 1990s following the Iran–Iraq War. However, the country has since then launched a robust domestic rearmament program, and its inventory has become increasingly indigenous. According to Iranian officials, most of the country's military hardware is domestically manufactured, and the country had already become an exporter of arms by the 2000s. Unable to import weapon systems from abroad due to international and U.S. sanctions, and suffering from an increasingly aging air force fleet, Iran has invested considerable funds into an ambitious ballistic and cruise missile program for long-range strike capability, and has manufactured different types of arms and munitions, including tanks, armoured vehicles and drones, as well as various naval assets and aerial defense systems.