With a presence in nearly every city and town across Iran, the paramilitary Basij volunteer corps has an ever-increasing influence on life in the Islamic Republic. Authorities created the Basij, which means mobilization in Persian, just after the country's 1979 Islamic Republic. It is part of Iran's powerful Revolutionary Guard.

The Basij has its roots as volunteer fighters during the 1980-88 war with Iraq. It then developed as a grass-roots defender of the system – taking on roles such as Islamic morality police at checkpoints and parks or as shock troops busting up pro-reform gatherings or publications. Precise numbers on Basij membership are not published, but some estimates range as high as 1 million or more.

It responds to emergencies like earthquakes and other natural disasters. It also has its influence online as well: The Basij has a group of hackers made up of university teachers, students and clerics that launch attacks on websites of “enemies”, a state-backed newspaper reported in 2011. It also monitors social media as well and will begin teaching “drone-hunting” to students. Basij branches can be found in all governmental bodies, universities and schools. Volunteers often enjoy favorable treatment from the government, particularly in securing jobs in the public sector.

In this Thursday, August 22, 2013 photo, female members of the Basij paramilitary militia load their rifles during a training session in Tehran, Iran. With a presence in nearly every city and town across Iran, the paramilitary Basij volunteer corps has an ever-increasing influence on life in the Islamic Republic. (Photo by Ebrahim Noroozi/AP Photo)

In this Thursday, August 22, 2013 photo, a female member of the Basij paramilitary militia aims her rifle as a trainer assists her during a training session in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)

In this Thursday, August 22, 2013 photo, female members of the Basij paramilitary militia march during training session in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)

In this Thursday, August 22, 2013 photo, a female member of the Basij paramilitary militia receives bullets during a training session in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)

In this Thursday, August 22, 2013 photo, a trainer of the Basij paramilitary militia shows female Basij members how to use an AK-47 rifle during a training session in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)

In this Thursday, August 22, 2013 photo, female members of the Basij paramilitary militia attend a training session in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)

In this Thursday, September 19, 2013 photo, members of the Basij paramilitary militia attend a training session, in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)

In this Thursday, September 19, 2013 photo, members of the Basij paramilitary militia fire their weapons during a training session, in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)

In this Thursday, September 19, 2013 photo, members of the Basij paramilitary militia listen to their trainer during a training session in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)

In this Thursday, August 22, 2013 photo, a trainer walks past female members of the Basij paramilitary militia during a training session in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)

In this Thursday, August 22, 2013 photo, a female member of the Basij paramilitary militia aims a rifle as a trainer looks over her shoulder in Tehran, Iran. (Photo by Ebrahim Noroozi/AP Photo)