The Islamic State group released a video on Friday purporting to show the killing of British aid worker Alan Henning. In the video, a masked militant also threatens the life of U.S. citizen Peter Kassig.
The short video titled "Another Message to America and its Allies" shows the two hostages wearing orange jump suits in a desert landscape alongside masked militants dressed in black. At the start of the clip, a man identified as Henning is seen kneeling. The video then shows a second hostage who the militants identify as Kassig.
"Obama, you have started your aerial bombardment of Shams (Syria), which keeps on striking our people, so it is only right that we continue to strike the neck of your people," the masked militant in the video says, according to the Associated Press.
Peter Kassig is a 26-year-old American aid worker and former Army Ranger.
Hours after the release of the video, the Kassig family released a statement confirming their son is being held by the Islamic State group. The family also offered their condolences to the relatives of Alan Henning.
Kassig briefly deployed to Iraq in 2007 before receiving an honorable discharge on medical grounds. After leaving the military, he trained as a medic and worked with Syrians affected by the country's devastating civil war. “We each get one life and that’s it,” Kassig told CNN in 2012. “This is what I was put here to do,” he added, referring to his aid work. “I guess I’m just a hopeless romantic and an idealist.”
Kassig eventually started his own aid group to help victims of the Syrian conflict in Lebanon, Turkey and Syria, called Special Emergency Response and Assistance. SERA focused on providing refugees with medical and other supplies, but recently suspended its work in Syria citing the security situation in the country.
Last October, the Daily Beast reported that Kassig was working in a hospital in Syria’s Deir Ez-Zour.
Childhood friend David Zoeller described Kassig as "selfless" and "altruistic in the clearest definition of the word."
"The happiest I ever saw him was when he was over there and helping people," Zoeller told The Huffington Post. "He felt like he was doing something good for the world, trying to make a difference, and within that I think he found peace within himself, a sense a purpose."
Zoeller told HuffPost that when he found out about his friend's disappearance last year, he was asked not to go to the media.
It was not immediately clear when Kassig was kidnapped.
Friday's video is the fourth such clip to be released by the Islamic State. The militants earlier claimed responsibility for the deaths of American reporters James Foley and Steven Sotloff and British aid worker David Haines.
Sebastian Murdock contributed to this report.