an address to the Revolutionary Guards during the Iran hostage crisis, Khomeini ordered the creation of an army of "twenty million Iranians" (Artesh-e bis million), proclaiming: "Equip yourself, get military training and train your friends. Give military training to those who are not trained. In an Islamic country, everyone should be a soldier and have military training. ... a country with 20 million young people [should have] 20 million riflemen, an army of 20 million" This pronouncement and Article 151 of the constitution, which calls for the government to “provide a program of military training, with all requisite facilities, for all its citizens, in accordance with the Islamic criteria, in such a way that all citizens will always be able to engage in the armed defense of the Islamic Republic of Iran,” are believed to refer to the Basij. While “Iranian official estimates sometime put their total part-time and full-time strength at more than 20 million", others estimate the Basij as having "a core strength of 90,000, and up to 600,000" (CSIS, 11 January 2018, p. 4); at 100,000 with "hundreds of thousands of additional Basij could be mobilized in the event or an all-out war” (CRS, 23 May 2018, p. 18). The Basij are "the most visible symbol" of the Pasdaran’s strength, whose members "can be seen on street corners in every Iranian city". They are (at least in theory) subordinate to, and receive their orders from, the Iranian Revolutionary Guards and current Supreme Leader Ayatollah Khamenei. However they have also been described as "a loosely allied group of organizations" including "many groups controlled by local clerics." Currently, the Basij serve as an auxiliary force engaged in activities such as internal security as well as law enforcement auxiliary, the providing of social service, organizing of public religious ceremonies, and as morality police and the suppression of dissident gatherings. Quds Force The elite Quds Force (or Jerusalem Force), sometimes described as the successor to the Shah's Imperial Guards, is estimated to be 2,000–5,000 in number. It is a special operations unit, handling activities abroad. The force basically does not engage directly. Aerospace Force Navy IRGC started naval operations using mainly swarm tactics and speedboats during "Tanker War" phase of the Iran–Iraq War. IRGC Navy and the regular Artesh Navy overlap functions and areas of responsibility, but they are distinct in terms of how they are trained and equipped—and more importantly