Story highlights Egyptian President says his country reserves the right to retaliate for the killings

ISIS' "barbarity knows no bounds," the U.S. government says in statement

ISIS releases a video Sunday showing what appeared to be a mass execution

(CNN) In a new propaganda video released Sunday by ISIS, the militant group claims to have beheaded over a dozen members of Egypt's Coptic Christian minority on a Libyan beach.

The highly produced video shows an apparent mass execution with jihadists in black standing behind each of the victims, who are all are dressed in orange jumpsuits with their hands cuffed behind them.

The five-minute video, released by the terror group's propaganda wing al-Hayat Media, includes a masked English-speaking jihadi who says, "The sea you have hidden Sheikh Osama bin Laden's body in, we swear to Allah, we will mix it with your blood."

Then on cue, all the victims are pushed to the ground and beheaded.

ISIS has imposed its brutal rule on the large areas of Iraq and Syria that it controls, but the beheadings of the Egyptians appears to have been carried out by an affiliate of the militant group in Libya.

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