ISIS released a video yesterday which appears to show the extremist group beheading 21 Coptic Christians from Egypt who were kidnapped in Libya, officials say. 

According to Reuters, the video shows the victims being led to a beach by the extremists, forced to kneel, then killed: 

A caption on the five-minute video read: The people of the cross, followers of the hostile Egyptian church. Before the killings, one of the militants stood with a knife in his hand and said: Safety for you crusaders is something you can only wish for.

The victims were reportedly Egyptian workers seized from Sirte during raids in December and January. Their deaths were confirmed yesterday by the Libyan parliament. 

Egyptian President Abdel Fattah al-Sisi has announced seven days of mourning, and BBC News reports that Egypt responded by bombing ISIS in the Libyan city Derna. 

[via Reuters and BBC News]