Pope Francis said Wednesday the world was at war but argued that religion was not the cause, as he arrived in Poland a day after jihadists murdered a priest in France.

"We must not be afraid to say the truth, the world is at war because it has lost peace," the pontiff told journalists aboard a flight from the Rome to Krakow.

"When I speak of war I speak of wars over interests, money, resources, not religion. All religions want peace, it's the others who want war."