Story highlights Syrian activists are taking the fight to ISIS over social media

They hope to counter the terror group's online propaganda

The online taunting has caught the attention of ISIS' central command

(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 can'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.

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