The Islamic State of Iraq and Syria has released another chilling and graphic video of a hooded militant claiming to have beheaded U.S. aid worker Peter Kassig. The footage showed a militant standing over a decapitated head. it was not immediately known whether the severed head belonged to the 26-year-old hostage who was taken in 2013.

According to recent reports of international media, U.S. President Barack Obama has confirmed Kassig's death in a statement he released last November 15. Mr Obama sent his prayers and condolences to the family of Kassig while heading to Joint Base Andrews in Maryland aboard Air Force One.

The president announced that Abdul Rahman, the name Kassig gave himself when ISIS captured him, was taken in an "act of pure evil." He once again called ISIS a terrorist group that the world "rightly associates with inhumanity."

The latest ISIS beheading video was posted in Web sites the extremist group had used in past propaganda videos. The footage appears to be another warning to the U.S. that ISIS militants will continue to exercise brutality if the Western powers do not abandon airstrikes against them.

In the 16-minute video, the militant speaks with a British accent despite the distorted quality of his voice in an apparent effort to hide his identity. Referring to the severed head, the militant said it belonged to Peter Kassig who was a U.S. citizen and fought against the Muslims in Iraq while serving as a soldier. He converted to Islam and returned to Iraq as an aid worker to help victims of war.

A mass beheading of Syrian soldiers was also shown in the video as the main speaker identifies their location as Dabiq, a small town in the Syrian province of Aleppo near the Turkish border. The ISIS militants in the video warned that other U.S. soldiers will also meet the same fate as Kassig's.

Addressing Mr Obama, the militants accused the president of hiding U.S. forces among Western-backed Kurdish fighters, Syrian rebels and Iraqi military troops. They said they were "eagerly waiting" for the rest of the U.S. troops to arrive to join the first American crusader buried in Dabiq.

Meanwhile, experts believe the latest ISIS beheading video as apparent "act of desperation." In a report by CNN, Haras Rafiq of the Quilliam Foundation said the world should expect more barbaric and brutal videos as ISIS becomes desperate amid continued airstrikes. He believes ISIS is trying to show they remain strong even as the U.S. and coalition forces gain more ground against the extremist group.

(Source: YouTube/Randy Rodriguez)