Pope Francis has led a global prayer for peace at the annual Lenten penitential service in St Peter's Basilica, Rome.

He consecrated all humanity - especially Russia and Ukraine - to the Immaculate Heart of Mary, and said the act expressed complete trust in the Virgin Mary in the midst of the "cruel and senseless war" in Ukraine.

In his homily at the Celebration of Penance at St Peter's Basilica in Rome, Pope Francis reflected on humanity’s need for God’s forgiveness and on the meaning of the Consecration.

"This is no magic formula but a spiritual act. It is an act of complete trust on the part of children who, amid the tribulation of this cruel and senseless war that threatens our world, turn to their Mother, reposing all their fears and pain in her heart and abandoning themselves to her", he said.

In Ireland, the International Eucharistic and Marian Shrine in Knock joined in the global prayer for peace along with clergy, lay people and the religious around the country.

During his homily, Archbishop of Dublin Dermot Farrell said history showed that neither war or violence had ever solved problems.

"The story of this island in the last 30 years is the story of people whose feet have been "guided on the way of peace", he said

Archbishop Farrell said the "unwarranted war" unveiled not only the horror of its victims, "but also, and equally frightening for us, all the poverty of the aggressor".

He said: "While, cynically proffering freedom, all that ultimately on offer is violence, gratuitous violence, and the loss that follows in its wake: not just loss of life, but loss of place, loss of dignity, loss of hope."

Students and staff at the national seminary of St Patrick's College in Maynooth, where there is a close association with a seminary in the Ukrainian city of Ivano-Frankivsk, were also led in prayer by Seminary Rector, Father Tomás Surlis.

Fr Surlis said a number of seminarians from Ivano-Frankivsk had been in formation in Maynooth in recent years.

Pope Francis' decision to consecrate Russia, Ukraine and the whole of humanity to the Immaculate Heart of Mary is in keeping with the tradition of the Catholic Church's Magisterium, which has always looked to Mary in difficult times.