. . . bearded plainclothes militiamen have been attacking and harassing the demonstrators in Tehran this past week. These are Basijis, members of a civilian paramilitary organization founded by Ayatollah Ruhollah Khomeini in 1979. It was conceived of as a civilian auxiliary force subordinate to the Revolutionary Guards, and so it has functioned over the past three decades.
The backbone of the Basij comprises 2,500 Al-Zahra (for women) and Ashura battalions, numbering 300–350 personnel each. The IRGC aims to arm 30 percent of these battalions with semi-heavy and heavy weapons. However, all members of the battalions are trained to use light arms and rifles. Since Major General Mohammad Ali Jafari assumed command of the IRGC on September 1, 2007, the Basij have received extensive organizational and logistical support by the Revolutionary Guards that has enabled it to form 30,000 new combat cells, each of them 15-20 members strong, named Karbala and Zolfaqar. These units cooperate closely with the army of the IRGC.
The Basij-e Mostaz’afin, (literally Mobilization of the Oppressed in Farsi), officially known as the Basij Resistance Force (Nirouye Moqavemate Basij), has branches in every town.
The Basij has a history of martyr-style suicide attacks dating back to the Iran-Iraq War, 1980–1988. Today, its main tasks are thought to assist locally against conventional military defense as well as quell civil uprisings. In addition, one of the Force’s key roles has been to maintain internal security, including monitoring internal threats from Iranian citizens and acting as a “static militia force.” The state of training and equipment readiness for the Basij is believed to be low. No major weapons systems have been reported for the inventory of the Basij.
UPDATE 20090622: Photographs of Iran’s Feared Basiji Special Forces