Extremist groups in the Middle East, including the Islamic State, must be stopped with sanctioned military force and through dialogue, said a Vatican statement.

"One cannot be silent, nor [can] the international community remain inactive, in the face of the massacre of persons," said the statement issued Oct. 4 at the end of a three-day Vatican summit on the plight of Christians in the Middle East.

"The participants at the meeting reaffirmed that it is licit to stop the unjust aggressor, always in accordance with international law," it said.

Pope Francis convened the Vatican summit Oct. 2-4 because of his growing concern and desire to do something about the dramatic situation Christians and other religious and ethnic minorities are facing in the region.

Those called to the summit included the seven Vatican nuncios based in Syria, Jordan-Iraq, Egypt, Israel-Palestinian territories, Iran, Lebanon and Turkey, as well as top officials from the Vatican Secretariat of State, the Vatican's permanent representatives at the United Nations in New York and Geneva, as well as from Vatican offices dealing with issues concerning refugees, charitable aid and Eastern churches.

A Vatican communique marking the end of the talks said, "The activity of some extremist groups is a cause of grave concern, particularly the so-called 'Islamic State,' whose violence cannot be met with indifference."

In the face of "the massacre of persons merely because of their religion or ethnicity, in the face of decapitations and crucifixions of human beings in public squares, in the face of the exodus of thousands of persons and the destruction of places of worship," the world cannot remain indifferent and something must be done, it said.

While the summit participants supported an internationally sanctioned armed response to stop an unjust aggressor, they said that "the resolution of the problem cannot be entrusted solely to a military response."

"The problem must be dealt with more radically by addressing the root causes which are exploited by fundamentalist ideology," it said.

Muslim, Christian and other religious leaders need to do more, cooperating to promote dialogue and mutual understanding as well as clearly denouncing the exploitation of religion to justify violence, it said.

Christians who have been forced "in a brutal manner" to flee from their homes must be guaranteed "the right to return in conditions of adequate security" as well as be free to work and build a future in the land where they and their ancestors have lived for more than 2,000 years.

"One cannot resign oneself to conceiving of the Middle East without Christians," it said. Christians have been a critical part of society and "they play a fundamental role of peacemaking, reconciliation and development."

At a Mass with participants Oct. 4, the feast of St. Francis of Assisi, Cardinal Pietro Parolin, Vatican secretary of state, said it is "painful to see how persistent and active the forces of evil are" in the region, especially "the conviction that violence and terrorism are methods that can be used to impose one's desire for power" or even one's religion on another. "This is clearly a perversion of the authentic meaning of religion."

One task of the nuncios and the Vatican representatives to the United Nations, he said, is to remind governments and international organizations of "their obligation to guarantee peace and security under the terms established in international law with the aim of putting the aggressors in a situation where they can no longer cause harm."