© AFP/Getty ImagesA masked militant threatens to execute British hostage Alan Henning in a video released Sept. 13.
The video ended with an Islamic State fighter threatening a man they identified as an American.
"Obama, you have started your aerial bombard of Shams (Syria), which keep on striking our people, so it is only right that we strike the next of your people," a masked militant said.
The Associated Press could not immediately verify the video's authenticity, though it was released in the same manner as other Islamic State group videos.
This is the fourth such video released by the Islamic State group. The full beheadings are not shown in the videos, but the British-accented, English-speaking militant holds a long knife and appears to begin cutting the three men, American reporters James Foley and Steven Sotloff and British aid worker David Haines.
Henning, 47, nicknamed "Gadget," had joined an aid convoy and was taken captive on Dec. 26, shortly after crossing the border between Turkey and Syria.
If I am an extremist of any order and I want to show the world what I am capable of, the last thing I would do is hide behind a mask so that I could not be identified. If I was standing up for something that I was pationate about I would definitely want to be identified with an organization that stood for something that was fighting a cause worth fighting. I distrust this to the exteme.