Pope Francis delivers the Angelus noon prayer in St. Peter s Square at the Vatican, Sunday, Feb. 27, 2022. AP
"Let the weapons fall silent," he said. "God is with those who seek peace, not those resorting to violence."
The Argentine pontiff also called for the "urgent" opening of humanitarian corridors to allow civilians to escape the onslaught.
"I am thinking of the elderly, of all those at the moment seeking refuge, of mothers fleeing with their children," he said.
"They are brothers and sisters for whom it is urgent to open up humanitarian corridors and who must be welcomed."
The UN refugee agency UNHCR says more than 368,000 people have fled Ukraine since Russia invaded on Thursday.
Many of those escaping to neighbouring countries have crossed over into Poland, where the authorities have counted some 156,000 crossing since that date.
Others have also headed to Moldavia, Hungary, Slovakia and Romania