That announcement came today as President Barack Obama flew back to Washington from Hawaii after a trip last week to the Asia Pacific region.
In the video released today, a militant claimed to have killed the 26-year-old Kassig.
Kassig served in an Army special operations unit in Iraq and after he was medically discharged, he formed an aid organization in Turkey to help Syrian refugees.
The Indianapolis man delivered food and medical supplies, and provided care to wounded Syrian civilians before he was seized in eastern Syria last year.