Pope Francis gave an impromptu call for peace this weekend, urging those fighting in the Middle East, Iraq and Ukraine to end their conflicts.

"Please stop, I ask you with all my heart, it's time to stop. Stop, please," the Pontiff pleaded, his voice cracking with emotion as he addressed those gathered in St Peter's Square yesterday.

Commentators have said that the Pope was deviating from his usual scripted speech, apparently overcome following weeks of intensified violence around the world. As the cameras zoomed in, reports suggest that he was seen blinking back tears.

More than a thousand people have been killed since the outbreak of the current the conflict in Gaza, most of them innocent civilians. Among them are 218 children – some as young as three months old – according to the latest figures from Unicef.

Last week's ceasefire in the Central African Republic has also broken down, and the extremist Muslim group Islamic State continues to gain momentum in Iraq and Syria, where Christians are being driven from their homes.

"Brothers and sisters, never war, never war!" the Pope continued.

"I am thinking above all of children, who are deprived of the hope of a worthwhile life, of a future. Dead children, injured children, mutilated children, orphaned children, children whose toys are things left over from war, children who can't smile anymore."

In a call for unity in the face of global conflict, the Archbishop of Canterbury wrote to Pope Francis, urging the Anglican and Catholic churches to stand together, despite their theological differences.

"There is...so much troubling our world today that our common witness to the Gospel is of more importance than ever," Archbishop Welby wrote in a letter that was sent to church leaders, including Francis.

"There is conflict in many regions of our world, acute poverty, unemployment and an influx of oppressed people driven away from their own countries and seeking refuge elsewhere.

"We need each other, as we, as churches empowered by the Holy Spirit, rise to the challenge and proclaim the good news of our Lord and Saviour Jesus Christ and strive for closer fellowship and greater unity."

The letter came in the wake of the Church of England's decision to ordain women bishops; a move which arguably solidified its separation from the Catholic Church.

However, both the Pope and the Archbishop have proved keen to encourage unity in disagreement since their respective appointments last year, and Welby underlined in his letter a desire to continue seeking a positive way forward.

"The Church of England continues in its quest to make our unity more visible with those with whom we are in communion, and to seek greater unity with those with whom we are not yet in communion," he wrote.

"Some of our Sister Churches in communion will share the joy of those in the Church of England, who welcome the development of having women in the episcopate. But we are also aware that our other ecumenical partners may find this a further difficulty on the journey towards full communion."

Welby concluded: "There is, however, much that unites us, and I pray that the bonds of friendship will continue to be strengthened and that our understanding of each other's traditions will grow."