"God weeps, Jesus weeps," Pope Francis said on Thursday, in a damning critique of a world bent on war.

"Today, Jesus weeps...because we have chosen the way of war, the way of hatred, the way of emnities," the pontiff said in his homily, less than a week after the terror attacks that killed 129 people in Paris.

"There are wars today everywhere, and hate...We should ask for the grace to weep for this world, which does not recognise the path to peace. To weep for those who live for war and have the cynicism to deny it.

"God weeps, Jesus weeps."

While the world looks forward to Christmas, with "lights, parties, Christmas trees and nativity scenes...it's all a charade," Francis continued. "The world continues to wage war. The world has not understood the way of peace."

He branded conflicts around the world "useless slaughters", and said that those "who make war are damned".

"War can be justified for many reasons. But when the world is at war, as it is today...there is no justification," Francis added.

After war, all that will be left is "ruins, thousands of children without education, so many innocent victims: and lots of money in the pockets of arms dealers."

Following last Friday's attacks in Paris, the Pope condemned "this new manifestation of maddening, terrorist violence and hatred".

A statement from the Vatican released labelled the attacks "an attack on peace for all humanity" and called for "a decisive, supportive response on the part of all of us as we counter the spread of homicidal hatred in all its forms."

The Pope has also insisted that fears about further attacks should not stop countries, and particularly the Church, from welcoming refugees who have fled violence and persecution in the Middle East.

"We in the Church are called to be welcoming to all who seek to enter the fold of the Good Shepherd," he said during his weekly address in St Peter's Square on Wednesday.

"May the doors of our Christian homes be signs and symbols of the door of God's mercy, a door ever open to all who knock and desire to meet Jesus."