( CNN ) Hidden , but vocal , average Syrians are questioning one of the most feared terror groups in the world and attempting to hold them accountable for crimes committed against the civilian population . From an undisclosed location , a Syrian activist operating under the pseudonym Abu Rafiq spoke to CNN about the war taking place on one of ISIS 's main front lines -- social media . The targets of the grassroots offensive are foreign fighters , notorious for using their Twitter and Facebook accounts to encourage young people to join their jihad . `` We would like to deliver this message to those who are joining ISIS especially from Europe , America , and some Arab countries and make them understand this is not the way , and this is not humility and this is not Islam , '' Abu Rafiq says , `` You ca n't just go and let some guy brainwash you and make you think you will go to paradise . '' A handful of natives split evenly inside the ISIS strongholds of Raqqah and Abu Kamal recently launched the hashtags `` Scream from al-Raqqah '' and `` Abu Kamal Under Fire '' to heckle ISIS extremists and share photos and news from the occupied cities . Some of the images are grotesque ; one shows a decapitated man tied to a pole with his head in his lap , a warning of the consequences that may befall any who violate the terror group 's draconian rule . Other images seem to act almost as a proof of life -- a small sheet of paper held close to the camera with the name of Abu Rafiq 's group scribbled in blue ink , and in the background a recognizable landmark . `` We are hear ( sic ) and we continue to reveal ISIS 's crimes , '' a caption on Twitter reads . Taking these types of photographs has already landed two of the activists in the custody of jihadis , according to Abu Rafiq who said that ISIS did not realize they were part of an organized opposition group and released them after a few days . But at least one endured torture at the hands of his captors , he said . `` The regime played the media card and ISIS did the same , and they are both very good at this , '' Abu Rafiq said explaining the importance of press coverage . `` So I thought we have to do something about this , and all of the Syrian people thought the same , so I am one of those who joined against ISIS . '' They were once taxi drivers and medical students , but now these activists are among the brave few engaging ISIS militants directly online -- questioning their beliefs and then posting the interactions for the world to see . `` Look at the murders of ISIS they cant ( sic ) even make excuses because they are brainwashed and they are like pieces on a chess board and when they are cornered they run away , '' wrote one user above a screen shot showing his account had been blocked by an ISIS fighter after he badgered him online . The online taunting caught the attention of ISIS 's central command structure in Syria , and a sleeper cell was ordered to find and destroy the clandestine group , according to a letter Abu Rafiq claims was leaked to his organization . The team of activists has yet to see a crackdown , but remains vigilant . `` We are not scared . It is just a letter . Because when you take a photo in front of ISIS members you are risking your life to deliver the truth from on the ground , so we are used to it , '' he shrugs . Abu Rafiq claims that some foreign fighters are defecting from ISIS , something reported by other activists and local media . He points to a literal sign of this trend -- a billboard warning truck drivers not to pick up or transport jihadis across the country . `` It shows how scared and worried they are because the number defecting is more and more , so they are telling drivers not to help them or take them anywhere , '' he said . Abu Rafiq 's underground network is modest so far , but similar groups in the area that have more support and resources -- including one calling itself `` Raqqah is Being Slaughtered Silently '' -- have been threatened with death for publishing reports on the ISIS operation in their hometown . `` Syrian people are very patient , but we have a limit , '' he told CNN . `` What happens with Assad , it might happen with ISIS and with anyone else . I think that might happen very soon . ''
Syrian activists are taking the fight to ISIS over social media . The group has been using Twitter and Facebook as a way of recruiting new members, but it is also trying to use its own propaganda channels on YouTube and other sites like Reddit or 4chan in The online taunting has caught the attention of ISIS ' central command .