On Sunday, Pope Francis issued his harshest condemnation of the Ukraine war yet, saying the “unacceptable armed aggression” must end.

Speaking to thousands of people gathered in St. Peter’s Square for his Sunday blessing, Francis called the bombing of hospitals and other civilian targets “barbaric” and lacking “any valid strategic reason.”

“In the name of God, I implore you: stop this massacre!” he exclaimed, adding that Ukrainian cities risk being “reduced to cemeteries.”