Russia versus Ukraine, Israel versus the Hamas and the US versus the Islamic State. At the rate international conflicts are being resolved by the use of arms and force, World War III has actually started on a piecemeal, Pope Francis warned on Saturday.

Horrified by the rash of big crimes, massacre of the innocent lives and destruction of cities and monuments, the pontiff warned of a major global military and armed crisis while visiting Italy's biggest cemetery to remember a hundred years when World War I erupted.

The leader of the 2-billion strong Roman Catholic Church condemned war as a sign a madness at the memorial to 100,000 Italian soldiers at the Redipuglia cemetery.

In his homily, Pope Francis urged the faithful, quoted by BBC, "Humanity needs to weep, and this is the time to weep ... Even today, after the second failure of another world war, perhaps one can speak of a third war, one fought piecemeal, with crimes, massacres, destruction."

His strong words reiterates his previous call in the past few months to end the conflicts in Iraq, Syria, Gaza, Ukraine and portions of Africa, although in August, he said the use of force to stop the unjust aggression by Islamic State extremists - who have beheaded at least two American journalists and killed or displaced thousands of people in Iraq and Syria - is justified.

Pope Francis would not be the pontiff had his grandfather, Giovanni Bergoglio, perished when he fought in World War I in a bloody campaign along the Isonzo River, near the graveyard where the pontiff visited. After he survived the war, Bergoglio emigrated to Argentina where Jorge Mario Bergoglio - who eventually became bishop of Buenos Aires - grew and became a priest.

The Isonzo River is not part of Slovenia, near the Italian border.

"I have heard many painful stories from the lips of my grandfather," Pope Francis said of his paternal ancestor who was drafted when he was 30 and awarded a certificate of good conduct and 200 lire at the end of World War I.

Redipuglia Mayor Antonio Calligaris is thankful for the papal visit on Saturday to the cemetery whose number of visitors to its monument has been dwindling the past two decades as people begin to forget the sacrifices of the 100,000 unknown soldiers buried in the cemetery.