A video purporting to show the mass beheading of Christian hostages has been released by militants in Libya claiming loyalty to the Islamic State group.
The video, released last night, depicted several men in orange jumpsuits being led along a beach, each accompanied by a masked militant.
The men are made to kneel and one militant, dressed differently that 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 said.
"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, believed to be Coptic Christians, are then laid face-down and simultaneously beheaded. The militant speaker then pointed northward and said, "We will conquer Rome, by Allah's permission."
Militants in Libya had been holding 21 Egyptian Coptic Christians hostage for weeks, threatening them with death.
The makers of the video identify themselves as the Tripoli Province of the Islamic State group - the Islamic militant group that controls about a third of Syria and Iraq.
The Egyptian government declared a seven-day mourning period and President Abdel Fattah el-Sissi convened an emergency national security meeting to discuss a response.
El-Sissi sent condolences to "the victims of terrorism", according to the presidency.
Qalini Sanyout, whose two nephews were among the hostages, answered the phone Sunday night amid the sound of wailing in the background.
"What can we say? Can someone tell us if this is true," he said repeatedly. "The whole village is in mourning. Men are covering their heads with dust and mud."