One US soldier killed in Iraq during rescue of more than 70 ISIS hostages

One U.S. soldier was killed in an operation that freed more than 70 ISIS hostages in Iraq, military sources confirm to Fox News.

The hostages were freed from an ISIS prison in northern Iraq near Tikrit. "People were chained to walls," one well-placed military source said.

"A mass atrocity was averted," a senior U.S. defense source tells Fox News. U.S. rescue forces moved in when it was apparent that ISIS hostage takers were planning to kill the hostages.

One military source says most hostages were Iraqi security forces, many were from the Iraqi Army, and some were police. Some of those rescued were part of the "Sunni Awakening," the fight against Al Qaeda that saw Sunnis alongside U.S. forces almost a decade ago. 

Fox News is told U.S. Special Operations forces killed 10 ISIS hostage takers during the overnight raid.