According to the site Pravmir, Metropolitan Onufry of Kiev told clergy politicians and soldiers must see past political differences and realise they are ultimately family.
He told clergy: "There is an unprecedented infowar going on."
"Propaganda is destroying brotherly relations between peoples and is even destroying relations between relatives.
"Where can we look for salvation?
"How can we overcome the problems and division, when the seeds of hostility and feud have been sown between the brothers in faith in abundance and they are already bearing their bloody fruit?"
He urged the two countries to take all possible steps to end the war and establish peace in the region, adding: "Any calls for military aggression and hostility are unacceptable for the clergy.
"We do not have the right to justify war by religious slogans in any case.
"I am calling on Orthodox people who are now on the different sides of this military conflict to see brothers in each other and begin to reconcile."
"There are no right-wing or left-wing people in graves.
"Children of our Church are now lying in graves in the eastern, central and western parts of Ukraine. If we don't stop the war in our hearts, it will only aggravate from the outside."