Pope Francis has begun a visit to Turkey today with the aim of strengthening ties with Muslim leaders while condemning violence against Christians and other minorities in the Middle East.

His three-day trip comes as Islamic State militants have captured swathes of Iraq and Syria just over Turkey's southern borders, declaring an Islamic caliphate and killing or driving out Shi'ite Muslims, Christians and others who do not share their ultra-radical brand of Sunni Islam. The Pope has repeatedly highlighted the plight of persecuted Christians in the region.

Officials said religious tolerance and fighting extremism would be high on the agenda during the visit. Francis is due to meet President Tayyip Erdogan and Mehmet Gormez, who is the top cleric in the majority-Muslim but constitutionally secular nation.
Turkey is sheltering an estimated 2 million refugees from Syria. 

In Istanbul, Francis will meet Ecumenical Patriarch Bartholomew, who is the spiritual head of 300 million Orthodox Christians worldwide. This comes as part of an effort to develop closer ties between the ancient western and eastern wings of Christianity.
They will issue joint calls on human rights and religious freedom as well as raising fears that Christianity is disappearing from its birthplaces in the Middle East, according to Rev. Dositheos Anagnostopoulos, spokesman for the patriarchate.

Syria's total Christian minority made up around 10 percent of the population of 22 million before its civil war began in 2011, while Iraq's Christian population has fallen by nearly 70 percent since the start of its 2003 war.

Francis said this week that while it was "almost impossible" to have a dialogue with Islamic State insurgents, the door should not be shut.

The Turkey trip will be the third by Francis to a mainly Muslim nation, after previous visits to Jordan and Albania.

Anagnostopoulos said Francis may pray inside Istanbul's Hagia Sophia, which was one of Christendom's greatest cathedrals for 900 years, one of Islam's greatest mosques for another 500, and is now officially a museum.

Such a move could upset some Muslims in Turkey, who would like to see it revived as a mosque.

There is controversy over the venue for his meeting with Erdogan. Francis, renowned for his humble lifestyle, will be the first guest in the president's lavish new 1,000-room palace.