Islamic State militants claim to have killed US hostage Peter Kassig — known as Abdul-Rahman Kassig since converting to Islam — in a new video released on a jihadist website and Twitter accounts linked to the group.
VICE News could not immediately verify the authenticity of the video. The footage does not show the execution, but features the same masked man with a London accent featured in previous beheading tapes of British and American hostages.
"This is Peter Edward Kassig, a US citizen of your country," the militant says in English, with a bloodied decapitated head at his feet. "Peter, who fought against the Muslims in Iraq whilst serving as a soldier in the American army, doesn't have much to say. His previous cellmates have already spoken on his behalf."
"But we say to you Obama, you claim to have withdrawn from Iraq four years ago. We said to you then that you are liars," the man continues in the near 16-minute video, which also shows the mass beheading of a group of Syrian soldiers.
"To Obama, the dog of Rome, today we are slaughtering the soldiers of Bashar and tomorrow we will be slaughtering your soldiers," the man dubbed "Jihadi John" by the British press says.
The fighter also threatens to "bury" US soldiers under the soil.
The US National Security Council is working to determine the authenticity of the footage and identity of the victim.
"If confirmed, we are appalled by the brutal murder of an innocent American aid worker and we express our deepest condolences to his family and friends," spokeswoman Bernadette Meehan said in a statement.
British Prime Minister David Cameron said he was "horrified by the cold blooded murder" in a tweet posted Sunday.
Kassig, 26, an American aid worker and former US Army Ranger, was kidnapped while delivering aid near Raqqa, Syria, on October 1, 2013. He was working with a humanitarian organization he founded called Special Emergency Response and Assistance, or SERA.
In a video appealing for his release early last month, Kassig's parents said their son had converted to Islam while in captivity and taken the first name Abdul-Rahman. Ed and Paula Kassig released a letter from their son last month, in which he wrote, "Mentally I am pretty sure this is the hardest thing a man can go through, the stress and fear are incredible but I am coping as best I can. I am not alone."
If authenticated, Kassig's death would be the fifth beheading of a Western captive since August. The Islamic State has previously posted videos showing the executions of US journalists James Foley and Steven Sotloff, and British aid workers David Haines and Alan Henning. Kassig appeared in the video of Henning's killing.
This is the only video that has not shown the execution itself, and unlike the others, does not feature a scripted message read by the captive.
It is unclear how many hostages remain in Islamic State captivity. Late last month, the group released two videos of current captive British photojournalist John Cantlie — one where he delivers a scripted message saying that the Sunni Muslim group treats its hostages "well," and another where he appears to report from the city of Kobane on the Syrian-Turkish border.
Kassig's parents issued the following statement on a Facebook page for their son on Sunday morning:
VICE News' Alice Speri contributed to this report.
Follow Liz Fields on Twitter:@lianzifields