On the flight to Poland for World Youth Day, Pope Francis on Wednesday responded to recent violence across the globe by saying that the world is at war.

"When I speak of war, I talk about it seriously, but it's not a war of religion. It's a war for money, for resources, for nature, for dominion. This is the war," Pope Francis told journalists on his July 27 flight from Rome to Krakow.

"Could one think of a religious war? No. All religions want peace. Others want war," he said. "Is that clear?"

Francis addressed the 70 journalists on board the papal plane when, as usual, he came to the back to greet them each individually and thank them for their work.

However, before going down the rows of eager writers and photographers on board, Fr. Federico Lombardi SJ, who will retire as Vatican spokesman after the trip, asked the Pope to offer some words on the "emotional days" at hand considering recent tragedies, including yesterday's attack in at a church in Rouen that left an 84-year-old priest dead.

In his comments, Francis noted that "for some time we have said that the world is in a piecemeal war. This is war."

Frequently what's happening is called "insecurity, but the true word is war. There was that of 14 (First World War), with its methods, then that of 39 to 45 (Second World War), and now there's another great war. This is what we are experiencing now."

This war is real, he said, noting that while it might not necessarily be "organic," it is organized.

He pointed to yesterday's attack in the French diocese of Rouen in which Fr. Jacques Hamel, 84, was killed by two Islamic State supporters while celebrating Mass.

"This holy priest who died precisely in the moment in which he offered prayers for the entire Church is one, but there are many Christians, many innocent people, many children," who suffer the same type of violence and hatred, he noted, pointing to Nigeria as an example.

"It's war: we're not afraid to tell this truth," Francis said, explaining that the world is at war because "it has lost peace."

The Pope then thanked the journalists for their work during World Youth Day, adding that youth "always speaks to us of hope."

"Now we hope that the youth tell us something and give us hope at this time," he said, and offered his thanks to those who "harbor condolences" for yesterday's attack, as well as French president Francois Holland, who "called me like a brother" after the incident, "and I thank him."

After offering these brief words to those on board, Pope Francis went down the rows of journalists to greet each of the 70 on board individually.