Pope Francis said on Friday he wanted to visit Turkey next year to celebrate the anniversary of the first council of the Christian Church.

"It's a trip that I desire to go on, with all my heart," the pontiff told a delegation of the Ecumenical Patriarchate of Constantinople in Istanbul, a Vatican statement said.

The early centuries of Christianity were marked by lively debate about how Jesus could be both God and man, and the Church decided on the issue at the First Council of Nicaea - now known as Iznik - in 325.

Earlier in May, the Ecumenical Patriarch Bartholomew, who is based in Istanbul, said Francis was planning to visit the city before heading to Iznik.

The Pope's travel agenda for this year includes a September trip to Asia and Oceania, the longest of his 11-year papacy, with stops in Indonesia, Papua New Guinea, Timor-Leste and Singapore.

At the end of September he is expected in Brussels and Luxembourg for a 4-day trip.