French journalist Nicolas Henin said he has lost "a close friend" following James Foley's killing by an Islamic State fighter.
Henin, who was held captive with Foley in Syria before being released in April, told ITV News his death was "horrific news".
"I lost not only a good colleague but also a close friend," he added.
A British family have told ITV News of their devastation after discovering a close relative is fighting with the Islamic State in Iraq.
A French journalist who was held hostage with James Foley in Syria has told ITV News it was "devastating" to see his murder.