Pope Francis tweeted this in several languages in the evening of February 25.
This morning, he broke all protocol and went himself to the Russian Embassy to express his distress at the war. (Normally, of course, it's the ambassadors who visit him at the Vatican.)
He has designated Ash Wednesday as a day of fasting for peace.
On January 26, the Bishop of Rome led a Day of Prayer for Peace in Ukraine. “Weapons are not the way,” he warned.
On February 9, he said: “Let us continue to implore the God of peace that tensions and threats of war be overcome through serious dialogue, and that the “Normandy Format” talks may also contribute to this. Let us not forget: war is madness!“
On February 13, he said, “I entrust every effort for peace to the intercession of the Virgin Mary and to the conscience of the political leaders. Let us pray in silence.”