Iraqi refugees have said that the ISIS rebels were hunting down non-Sunnis and people against the militants.
ISIS rebels have been methodically hunting down non-Sunnis and those opposed to the militants, refugees from the rebel-held towns have told the BBC.
ISIS reportedly demanded that soldiers and officials pledge allegiance to the Caliphate that was recently declared or give in to execution.
There are more than one million Iraqis who have fled from the country due to the militant activities of ISIS in the cities of Tikrit, Mosul and other parts of the northwest region.
The UN and Iraqi officials say that at least 2,461 people have been killed in June.
The ISIS has also holed up 49 Turkish citizens, 46 Indian nurses and 40 Indian construction workers, reports the BBC.