Pope Francis has denounced and expressed sadness on the beheading of the 21 Egyptian Christians in Libya at the hands of the Islamic State of Iraq and al-Sham (ISIS).

Deviating from his planned script on Monday before members of the Church of Scotland, Pope Francis decried the slaughter and emphasized the unity of all Christians regardless of the denomination they follow.

Speaking in his native Spanish, the Argentine pope used the ecumenical audience of Presbyterians to declare that the Copts were martyred for their faith — the faith of all Christians.

“Their only words were: ‘Jesus, help me!’ They were killed simply for the fact that they were Christians,” Pope Francis said.

“The blood of our Christian brothers and sisters is a testimony which cries out be heard. It makes no difference whether they be Catholics, Orthodox, Copts or Protestants. They are Christians!” the pontiff said. “Their blood is one and the same. Their blood confesses Christ. As we recall these brothers and sisters who died only because they confessed Christ.”

“The martyrs belong to all Christians,” the Catholic leader added.

On Monday, the Vatican’s spokesman said Pope Francis had telephoned Tawadros II, the Coptic pope, and told him that he shared the pain caused by the “barbaric murder of Christian Copts by Islamic fundamentalists.”

Meanwhile, both Libya and Egypt confirmed that Egypt had carried out a series of airstrikes against the Islamic terror group in Libya, killing about 50 militants.

“Egypt preserves the right to respond, with the appropriate manner and timing, in order to carry out retribution on those killers and criminals who are stripped of the most basic of human values,” President Abdel Fattah el-Sisi of Egypt said.

On the other hand, the Coptic Catholic patriarchate of Alexandria said that the beheading of the 21 Orthodox Christians had drawn together the Christians of Egypt. The tragedy “is uniting the entire country, Christians and Muslims. If their aim was to divide us, they have failed,” a spokesman said.