Pope Francis said that "increasingly alarming scenarios" are emerging in Ukraine and he urged all sides to refrain from actions that could cause suffering to the people in the region.
"Despite the diplomatic efforts of these past weeks, increasingly alarming scenarios are emerging," he said at the end of his weekly general audience on February 23.
"I ask all of the parties involved to abstain from any action that could cause still more suffering for the population," the pontiff added.
He said the threat of war in Ukraine had caused "great pain in my heart" and he urged leaders to make a serious examination of conscience before God about any actions they might take.
Speaking in a somber tone at the end of his address, Francis proclaimed Ash Wednesday, March 2, as an international day of fasting and prayer for peace.
Western leaders say Ukraine is facing the threat of a full-scale invasion from Russia after it amassed at least 150,000 troops on the border.
President Vladimir Putin defied the West and the United Nations by saying he was recognizing two separatist areas in eastern Ukraine as independent states and that he was ready to send troops there.