No atrocity is too gory for Islamic State (ISIS) militants to turn away from. In one of their latest barbaric acts, the jihadis executed a pregnant woman and took away her four children, after they tried to flee their village in Iraq, the Daily Mail reported.

Witnesses said the mother was executed by the ISIS militants after she and her children were caught trying to reach an Iraqi military base near the ISIS-occupied city of Mosul.

Reports said the children were taken away to another village under ISIS control.

This was just one in the lengthening list of atrocities committed by the Islamic terror group against women and girls in its captured territories across Iraq and Syria.

In June, the Tehran-based Al Alam International News Channel reported that ISIS fighters beheaded a 4-year-old girl in the Syrian stronghold of Raqqa, and even forced her mother to soak her hands in her daughter's blood.

"They rape women, take children to war, loot houses and threaten people in Raqqa with beheadings if they don't agree with their daughters' marriage with the ISIS members," a Syrian woman who escaped from ISIS captivity said.

ISIS has been relentless in committing acts of savagery and terror despite its continuing loss of territory reportedly as a result of the U.S.-led coalition's operations in Iraq and Syria.

However, CIA Director John Brennan said the coalition effort against ISIS has not been successful, suggesting that he would give the U.S. an "F" grade so far in this regard.

"Unfortunately, despite all of our progress against ISIL on the battlefield and in the financial realm, our efforts have not reduced the group's terrorism capability and global reach. The resources needed for terrorism are modest. The group would have to suffer even heavier losses on territory, manpower and money for the terrorist capacity to decline significantly," Brennan said at a congressional hearing in June this year.