Syrian activists risking their lives to report on life under Isis describe how life has changed in Raqqa

Abdul-Aziz al-Hamza, an activist from Raqqa is being Slaughtered Silently, said: 'There are rewards for anyone who kills one of us. We don't know the amount, but I am sure it's a big number'

Isis fighters parade in Raqqa, which became the group's de-facto capital in Syria in August 2014. (AP)

A network of Syrian activists working against Isis has exposed the barbaric reality of life in the city of Raqqa.

Raqqa is Being Slaughtered Silently (RBSS) are a group of citizen journalists which report on crucifixions, executions and general life in the so-called Islamic State.

Earlier this month, they reported that a 20-year-old jihadi had shot his mother in the head with an assault rifle in front of a crowd, after she was accused of apostasy.

Using around 70 contributors inside Raqqa and its surrounding area, the group gathers pictures, videos and firsthand accounts of life within the city.

Abdel-Aziz al-Hamza, co-founder of RBSS, described how life had changed within the headquarters of Isis in The Times Magazine.

"It was a normal city," he told the magazine. "You could do what you wanted: drink, smoke, whatever."

However, life drastically changed when Isis took control of the city in January 2014.

"They started to change the city. They painted the city black and started to kidnap its citizens and execute them."

He added: "But no one heard what was going on, so we decided to show the reality of life in the city, the reality of Isis.

"It was a duty for us. We used to fight the Syrian government regime, and now we had a regime that was even worse."

He went on to describe Raqqa as a "prison", in which only those with special permission to travel for medical reasons can leave.

RBSS is doing all it can to stop Isis recruiting civilians in Raqqa. Its supporters have been putting up anti-Isis posters and graffiti, and have even distributed a magazine containing subversive material with the same cover as an Isis publication.

Isis have hunted and killed the group's members, murdering filmmaker Naji Jerf, and beheading two others.

"There are rewards for anyone who kills one of us," Mr al-Hamza told The Times Magazine. "We don't know the amount, but I am sure it's a big number."