The Archbishop of Canterbury has condemned the Islamic State as "deeply evil" after footage emerged online on Sunday of militants executing 30 Christians in Libya.
The footage appeared to show two groups of Ethiopians, one of which was shot while the other group was beheaded.
It is believed that the Ethiopians were captured while passing through Libya on their way to Europe.
The militants can be heard describing the victims as "worshippers of the cross belonging to the hostile Ethiopian church".
Archbishop Justin Welby, the most senior bishop in the Anglican Communion, was in Egypt at the weekend to meet with religious and political leaders following the similarly brutal execution of 21 Egyptian Christians at the hands of Islamic State jihadists in Libya in February.
The February murder inspired Christians around the world when the victims could be heard crying out to Jesus moments before their deaths.
In an interview with the BBC at the weekend, Welby said: "I believe Islamic State is deeply evil - even to its own supporters if they stray one inch off what is seen as the right road."
Speaking in the British House of Lords last September, the Archbishop had given his support to military intervention to address the ISIS situation.
However, he said that ultimately the war against ISIS was ideological.
"It is also necessary, over time, that any response to ISIL and to this global danger be undertaken on an ideological and religious basis that sets out a more compelling vision, a greater challenge and a more remarkable hope than that offered by ISIL," he said.
"We must face the fact that for some young Muslims the attractions of jihadism outweigh the materialism of a consumer society."
He continued: "We must not rely on a short-term solution on a narrow front to a global, ideological, religious, holistic and trans-generational challenge.
"We must demonstrate that there is a positive vision far greater and more compelling than the evil of ISIL and its global clones.
"Such a vision offers us and the world hope, an assurance of success in this struggle, not the endless threat of darkness."
The following month, he said in an interview with Prospect magazine that religious leaders in the Middle East had "asked for armed assistance".