A caption on the video reads: “The people of the cross, followers of the hostile Egyptian church.”

Reuters says the Egyptian-based Middle East News Agency is reporting the Coptic Church has confirmed 21 Egyptian Christians believed to be held by Islamic State are dead.

The Christians were Egyptians who were kidnapped in December while working in neighbouring Libya.

The video shows militants in black marching captives dressed in orange jumpsuits to a beach where they are forced down onto their knees and then beheaded.

The Guardian reports on the content of the video describing how one militant, dressed differently than the others, addresses the camera in North American-accented English.

“All crusaders: safety for you will be only wishes, especially if you are fighting us all together. Therefore we will fight you all together,” he says. “The sea you have hidden Sheikh Osama bin Laden’s body in, we swear to Allah we will mix it with your blood.”

The men are then laid face-down and simultaneously beheaded. The militant speaker then points northward and says: “We will conquer Rome, by Allah’s permission.”

The President of Libya has called a seven-day period of mourning following the incident.

On its Facebook page, the Egyptian Coptic Orthodox Church said it was “confident” that those who beheaded the hostages would be punished.

“The Orthodox Church … is confident its homeland would not rest until the evil perpetrators get their fair retribution for their wicked crime.”

Image via Flickr.