President Michael D Higgins has led congratulations in Ireland following the election of the new Pope Leo XIV.
Mr Higgins said Cardinal Robert Prevost, an American, becoming Pope was "an immensely significant moment for all those of faith".
Mr Higgins said: "This is an immensely significant moment for all those of faith and goodwill around the world who look to the papacy for spiritual guidance, moral clarity and global leadership at a time described by his predecessor Pope Francis as needing the vocation of diplomacy.
"Pope Leo XIV assumes this important role at a time of great challenges for the world.
"I send Pope Leo my very best wishes as he begins his pontificate, and I welcome his statement that he is prepared to lead with compassion, wisdom and an enduring commitment to the values of peace, justice and human dignity."
The Taoiseach Micheál Martin said: "The scenes of great joy and celebrations in St Peter's Square are a reflection of the hopes and goodwill felt by people of the Catholic faith from all around the world towards the new Pope.
"I hope that this groundswell of best wishes towards Pope Leo XIV will give him strength and support as he takes on the immense responsibility of his pontificate.
"I know that he has the best wishes of all Irish people, of all traditions," added Mr Martin.
Archbishop Eamon Martin also welcomed the appointment of Pope Leo XIV.
In a statement, he said: "Pope Leo is a missionary at heart with a breadth of international experience and background - having ministered in three continents.
"His opening words about peace and 'building bridges' indicate that he wishes to work for reconciliation and unity in the Church and in the world.
"His choice of name suggests that a commitment to Catholic social teaching will be a hallmark of his papacy," said Dr Martin.
Election of Pope Leo a 'great honour' for US - Trump
US President Donald Trump hailed the election of Pope Leo XIV as a great honour for the US.
"Congratulations to Cardinal Robert Francis Prevost, who was just named Pope. It is such an honor to realize that he is the first American Pope. What excitement, and what a Great Honor for our Country," Mr Trump said on his Truth Social network.
"I look forward to meeting Pope Leo XIV. It will be a very meaningful moment!"
Mexican President Claudia Sheinbaum, whose country has the world's second-largest Catholic population, congratulated Pope Leo XIV on his election.
Ms Sheinbaum said she shared the pontiff's "humanist" values "in favour of world peace and prosperity".
British Prime Minister Keir Starmer said: "The election of Pope Leo XIV is a deeply profound moment of joy for Catholics in the United Kingdom and globally, and begins a new chapter for the leadership of the Church and in the world.
"I look forward to meeting the Holy Father and continuing to work closely with the Catholic Church here in the UK and internationally to advance our shared values and the common good."
In a letter to the Pope, Italian Prime Minister Giorgia Meloni said: "Italians will look to you as a guide and point of reference, recognising in the Pope and the Church that spiritual and moral authority that derives from its inexhaustible message of love, charity and hope, which flows from the Word of God."
French President Emmanuel Macron said: "A historic moment for the Catholic Church and its millions of faithful. To Pope Leo XIV, to all Catholics in France and around the world, I send a fraternal message. On this May 8th, may this new pontificate bring peace and hope."
In a statement, German Chancellor Friedrich Merz congratulated Pope Leo XIV, saying: "Through your role, you provide hope and guidance to millions of believers around the world in these challenging times.
"For many people, you are a beacon of justice and reconciliation. In Germany, people look to your pontificate with confidence and positive expectation.
"I wish you much strength, good health, and God's blessing for the tasks that lie ahead of you."
