Denouncing conflicts in Ukraine, Libya and elsewhere, and noting last week's deadly attack against school-children in Pakistan, the pontiff also lamented the thousands of victims of the Ebola apidemic in West Africa.
"Truly there are so many tears this Christmas," he said.
Delivering his second Christmas blessing, the popular Argentine pontiff, visibly moved and departing from his text, said vast numbers of children "are victims of violence, made objects of trade and trafficking".
Speaking to a large crowd massed outside Saint Peter's Basilica, the pope urged Ukrainians to "overcome tensions, conquer hatred and violence and set out on a new journey of fraternity and reconciliation".
He turned too to the violence wrought by Islamic State fundamentalists this year in Syria and Iraq.
"I ask him, the Saviour of the world, to look upon our brothers and sisters in Iraq and Syria, who for too long now have suffered the effects of ongoing conflict, and who, together with those belonging to other ethnic and religious groups, are suffering a brutal persecution."
He called for peace in "the whole Middle East" and continued efforts towards "dialogue" between Israelis and Palestinians.
The pope too urged peace in Nigeria "where more blood is being shed", as well as in Libya, South Sudan, the Central African Republic and the Democratic Reublic of the Congo.
He noted the victims of Ebola in Liberia, Sierra Leone and in Guinea and thanked those were "courageously" assisting the sick.