Pope Francis denounces the slaying of 21 Egyptians Copts in Libya by Islamic State of Iraq and Syria or ISIS.

According to Vatican Radio, on Monday Pope Francis denounces ISIS killing of 21 Coptic Christians in Libya.

The CBSNews cited that Pope Francis called Pope Tawadros II, the patriarch of the Coptic Orthodox Church to "express his profound participation with the pain of the Coptic Church for the recent barbaric assassination of Coptic Christians by Islamic fundamentalists," the Vatican spokesman said.

"The blood of our Christian brothers and sisters is a testimony which cries out to be heard," Pope Francis told a delegation from Scotland on Monday. "It makes no difference whether they be Catholics, Orthodox, Copts or Protestants. They are Christians! Their blood is one and the same. Their blood confesses Christ."

The Time reported that the 21 hostages who were killed by ISIS are believed to be laborers from Egypt and now they are "martyrs".

"Our brother Copts, whose throats were slit for the sole reason of being Christian, that the Lord welcome them as martyrs," Pope Francis said as he began his Mass on the report of The Economist.

The ISIS released the video on Sunday that shows the slaying of 21 Copts who were abducted last month. The said video is entitled "A Message Signed With Blood To The Nations Of The Cross" and it is a five-minute clip showing the beheading of the hostages Egyptian.

Meanwhile, the Express said that an Egyptian warplanes on Monday "targeted weapons storage sites and training camps in neighboring Libya" as part of the response to the mass beheading.