"Residents of the village of Mayadeen in Deir Ezzor province reported that IS hanged from a crossbar two boys aged under 18 near the HQ of the Hissba", the jihadist police, Observatory chief Rami Abdel Rahman told AFP.
"The children have been suspended by ropes from a pole since noon, and they were still there in the late evening," he said.
"Apparently, they were caught eating."
A placard was attached to the bodies reading "They broke the fast with no religious justification".
Throughout the month of Ramadan, which began on Thursday, believers abstain from eating, drinking, smoking and having sex from dawn until sunset.
IS, which controls swathes of territory across Syria and Iraq where it has created a self-proclaimed "caliphate", advocates an extreme view of the application of Islamic law, or sharia.
The jihadists do not hesitate to impose brutal punishments including beheadings, stonings, floggings and crucifixions.
Posted by Women Against Shariah on Tuesday, June 23, 2015