KRAKÓW, Poland (AFP) — 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.”

The brutal killing of an elderly Catholic priest during mass in France on Tuesday, in an attack claimed by the Islamic State group, has cast a shadow over Francis’s trip to headline a gathering of hundreds of thousands of young Catholics from across the globe in Krakow and increased concerns over security.

“This holy priest who died in the moment of offering prayers for the church is one (victim). But how many Christians, innocents, children?” Francis told journalists travelling with him.

“The word we hear a lot is insecurity, but the real word is war. The world has been in a fragmented war for some time. There was the one in 14, one in 39-45 and now this,” he said referring to World War I and II.

A string of terror attacks targeting civilians in Europe appears to have dampened turnout for the World Youth Day festival.

Around 200,000 pilgrims attended the opening mass on Tuesday, according to Krakow police, while organisers had originally expected around half a million.