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ISIS is releasing a video that reportedly shows the beheading of American hostage Steven Sotloff.  Site Intelligence Monitoring Service reported the news today.  The video warns governments to back away from "this evil alliance of America against the Islamic State." 

Steven Sotloff is a journalist from Florida who was abducted last year while he was covering the conflict in Syria.  His mother Shirley released a video last week pleading for his release. 

Site Intelligence Monitoring Service says a masked figure who appears in the video also issued a threat against a British hostage named David Haines.  

The U.S. is working to authenticate the video. State Department spokesperson Jen Psaki said if the video turns out to be real, it's sickening and a horrific terrorist act.  

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