Speaking at a service for tens of thousands of people at Saint Peter's Square in the Vatican today he said the war was a "folly" that was leading to "heinous massacres" and "atrocious cruelty" against defenceless people.
Without naming Russia directly, he asked: "What victory is there in planting a flag on a pile of rubble?"
On Wednesday, the Pope condemned the targeting of civilians in Ukraine, calling the discovery of bodies in Bucha near Kyiv a "massacre" and embracing a Ukrainian flag from the "martyred town".
The Pope has also expressed his willingness to contribute to halting the fighting in Ukraine and said he would be ready to travel to Kyiv.