ISTANBUL (AFP)

Pope Leo XIV wraps up a four-day trip to Turkiye Sunday after a warm welcome by its Christian community, before heading to Lebanon with a message of peace for the nation.

On his first overseas trip since being elected leader of the world's 1.4 billion Catholics, Leo met Turkiye President Recep Tayyip Erdogan before travelling to Iznik for a celebration marking 1,700 years since the First Council of Nicaea, one of the early Church's most important gatherings.

On Saturday, the American pope hosted thousands of worshipers who battled the rain to attend a public mass in Istanbul, with many traveling from across Turkiye to join the multilingual service, which left many moved by its beautiful and haunting choral interludes.

On his final morning, Leo was expected to attend a prayer service at the Armenian cathedral then lead a divine liturgy -- the Orthodox equivalent of mass -- at the Patriarchal Church of St. George before a final blessing.

He will have lunch with Patriarch Bartholomew I, the leader of the world's Orthodox Christians, a day after they signed a joint declaration in which they pledged to take "new and courageous steps on the path towards unity".

Despite doctrinal differences that led to the Great Schism of 1054, resulting in a split between the Roman Catholic Church in the West and the Eastern Orthodox Church, the two sides maintain dialogue and hold joint celebrations.

They also agreed to continue their efforts to establish a common date for Easter, which is currently celebrated by Catholics and Orthodox Christians on different days.

Pope Leo is the fifth pontiff to visit Turkiye, after Paul VI in 1967, John Paul II in 1979, Benedict XVI in 2006, and Francis in 2014.

He is expected to leave Istanbul 1145 GMT and fly to Beirut for a visit lasting until Tuesday.

The six-day two-nation trip is the first major international test for the first pope from the United States, who was elected head of the Catholic Church in May and whose understated style contrasts with that of his charismatic predecessor, Francis.

Leo's visit is eagerly awaited in Lebanon, a religiously diverse country of 5.8 inhabitants.