The Basij (Persian: بسيج) (officially Basij-e Mostaz'afin, literally "Mobilization of the Oppressed"), literally "Mobilisation Resistance Force") is a paramilitary volunteer militia established in 1979 by order of the Islamic Revolution's leader Ayatollah Khomeini. The force consists of young Iranians who've volunteered, often in exchange for official benefits. Currently 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 more famously policing of morals and the suppression of dissident gatherings. Basij is the name of the force; a basiji is an individual member.
The Basij are (at least in theory) subordinate to, and receive their orders from, the Iranian Revolutionary Guards and current Supreme Leader Ayatollah Khamenei, to whom they are known for their loyalty. They have also been described as "a loosely allied group of organizations" including "many groups controlled by local clerics." They have a local organization in almost every city in Iran.
As of October 2009 Mohammad Reza Naqdi was the commander of the Basij. The force has often been present and reacting against the widespread protests which occurred immediately after the 2009 Iranian presidential election and in the months following.