Marking Thursday's 75th anniversary of the Normandy landings during World War II, bishops from across the world said the operations recall the need for peace and the duty of gratitude to veterans.

Some 156,000 Allied forces landed on five beaches of Normandy June 6, 1944 to liberate the European continent from Nazi German occupation. About 4,400 Allied servicemen died that day, and there were between 4,000 and 9,000 German casualties.

Within a year of D-Day, Nazi Germany had been defeated.

Cardinal Marc Ouellet, prefect of the Congregation for Bishops, gave an address June 5 at the Abbey of Saint-Étienne in Caen, not far from the landing sites.

"Seventy-five years after the end of the Second World War, the memory of the victims of this massacre imposes on us a homage of respect and a duty to prevent conflicts by all means," he said.

"Believing in peace" implies "an increased rational commitment to transform the world according to the imperative of unconditional respect for the dignity of the human person, unfortunately undermined by ideological colonization hostile to the sanctity of human life," he said.

"In this difficult context, believing in peace also means relying on the efficiency of prayer for peace, since the Spirit of God directs human history towards its transcendent accomplishment with the imperfect but voluntary support of human freedoms."

Cardinal Ouellet lamented the terrible cost of the World Wars: "The bitter feeling of the monstrous cost of these conflicts remains a heavy legacy that does not erase what has been achieved in the positive and generous achievements in European reconstruction. That is why remembering the end of the last great conflict is a duty of respect for the too many victims of these tragedies and a permanent requirement for reflection and commitment to prevent such disasters from happening again in the future."

"There is a constant need for reflection and commitment to prevent such tragedies," he stated. "But man does not seem to have learned much from his past sufferings: we are experiencing a globalization of oblivion and indifference to the victims of today, and conflicts have not ceased to increase and fragment on all continents."

More in Europe

Archbishop Timothy Broglio of the US Military Services marked the anniversary saying: "On my last visit to Normandy in 2015 I was struck by the number of French men and women who came up to me and said: 'We will never forget what your countrymen did here.' Indeed it is important to remember and give thanks for the sacrifices made on the beaches of Normandy and elsewhere in Europe and in the Pacific Theater."

"We are continually reminded of the commitment of those who have gone before us and we pause on this 6th day of June to give thanks for those who 75 years ago made the ultimate sacrifice on the beaches of Normandy to liberate Europe from the Nazis and to defend the cause of freedom for all humanity. As we pause to honor their memory, we thank them for their sacrifice. As Christians, we pray for the repose of their souls and pray for their families. Can we forget all who lost their lives because of their religion or ethnic group? We recognize that all people are created in the image of God and pledge to live that belief in the day-to-day activities of ordinary life."

The archbishop said that "Christ reminds us there is no greater love than to lay down one's life for one's friends. We give thanks to God Almighty for all the brave servicemen and women who have faithfully kept the Lord's commandment to love their compatriots even to the point of death throughout the course of our nation's history from the time of its birth."

He added that "we ask God that their sacrifice not be in vain. We beg Him to transform our power to turn war into a force for peace, to transform our weapons into plowshares, to give us the ability to negotiate, to talk, and to listen. We pray to remain vigilant against the forces of evil in our troubled world, and to pour our energies into building lasting peace and justice among nations."

Pope Francis, in a May 31 letter to Bishop Jean-Claude Boulanger of Bayeux-Lisieux, reflected that the Normandy landings were "decisive in the struggle against Nazi barbarism and that they opened the way to the end of this war which so profoundly wounded Europe and the world."

"That is why I remember with gratitude all the soldiers who, coming from several countries including France, had the courage to commit themselves and to give their lives for freedom and peace. I entrust them to the infinitely merciful love of the Lord, as well as the millions of victims of this war, without forgetting those who, on the German side, fought in obedience to a regime animated by a deadly ideology."