Speaking at the Vatican on Monday before departing on a state visit to Asia, Francis was addressing ambassadors of 180 States which have diplomatic relations with the Holy See.
The Pope said humanity was engaged in "a true world war fought piecemeal" as he highlighted many of the ongoing conflicts around the globe, blaming a "breakdown of society and spawning violence and death".
"We see painful evidence of this in the events reported daily in the news, not least the tragic slayings which took place in Paris a few days ago. Other peoples are no longer regarded as beings of equal dignity, as brothers or sisters sharing a common humanity, but rather as objects," said the pontiff.
The pontiff acknowledged that the Middle East was "tragically embroiled" in conflicts which have lasted "far too long" with what he described as "chilling repercussions", due also to the spread of fundamentalist terrorism in Syria and in Iraq, he said.
Francis also urged leaders in the Muslim community to "condemn all fundamentalist and extremists", in the wake of the terror attacks in Paris.
"Religious fundamentalism, even before it eliminates human beings by perpetrating horrendous killings, eliminates God himself, turning him into a mere ideological pretext.
"In the face of such unjust aggression, which also strikes Christians and other ethnic and religious groups in the region, a unanimous response is needed, one which, within the framework of international law, can end the spread of acts of violence, restore harmony and heal the deep wounds which the ongoing conflicts have caused," said the Pope.
He prayed also that the parties in conflict in the Ukraine, "which has become a dramatic theatre of combat", may "through dialogue" respond to the efforts being made to end the hostilities and resolve the present crisis.
Vatican journalist Gerard O'Connel said it was a heartfelt appeal for peace. Speaking to Premier's News Hour from Rome, he said: "He feels it's a very dangerous moment in world history and governments have really to take responsibility, not just simply throw blame; they have to come in with concrete positive solutions."
America magazine journalist, Gerard O'Connel:
