(CBS) - The Islamic extremist group that has overrun parts of Syria and Iraq released a video that apparently shows the beheading of American journalist James Foley. The militant group also threatened to kill another U.S. journalist if the U.S. does not halt its airstrikes in Iraq.
The Islamic State of Iraq and Syria, known as ISIS, released a video titled "A Message to America" that was posted on several social media websites. YouTube removed a version of the video on Tuesday afternoon.
The video shows a militant using a knife to decapitate a man the group identifies as James Foley. Foley, a 39-year-old freelance journalist from Boston, disappeared in northwest Syria on Thanksgiving Day, Nov. 22 2012.
At the end of the video, a second hostage is seen. He is identified in the video as Time magazine photojournalist Steven Joel Sotloff. An ISIS extremist says Sotloff will be the next to die if the United States does not stop its attacks on ISIS positions in northern Iraq. CBS News has not confirmed the identity of the second American.
The video bears the logo of al-Furqan media, ISIS' main media distribution group.
The Obama administration said it had not determined whether the video is authentic.
"We have seen a video that purports to be the murder of U.S. citizen James Foley," National Security Council spokeswoman Caitlin Hayden said in a statement. "The intelligence community is working as quickly as possible to determine its authenticity. If genuine, we are appalled by the brutal murder of an innocent American journalist and we express our deepest condolences to his family and friends. We will provide more information when it is available."
Foley's family in New Hampshire said they had not received confirmation of the journalist's death.
"We know that many of you are looking for confirmation or answers. Please be patient until we all have more information, and keep the Foleys in your thoughts and prayers," they said in a statement posted on Facebook.
In 2002, American journalist Daniel Pearl was kidnapped by militants in Pakistan and later beheaded by al Qaeda member Khalid Sheikh Mohammed, who is now in U.S. custody.