Pope Francis has urged Muslim leaders to condemn the "barbaric violence" being committed in Islam's name against religious minorities in Iraq and Syria as he arrived in neighbouring Turkey for a delicate visit aimed at improving inter-faith ties.
Francis sought to offer a balanced message as he met Turkish political and religious officials at the start of his second trip to the Middle East this year. He reaffirmed that military force was justified to halt the Islamic State group's advance, and called for greater dialogue between Christians, Muslims and people of all faiths to end fundamentalism.
"As religious leaders, we are obliged to denounce all violations against human dignity and human rights," Francis told Mehmet Gormez, Turkey's top cleric and other religious officials gathered at the government-run Religious Affairs Directorate.
"As such, any violence which seeks religious justification warrants the strongest condemnation because the omnipotent is the God of life and peace."
Francis condemned the "barbaric violence" by IS against Christians, Yazidis and other religious minorities and the destruction of their places of worship.
The Vatican has voiced particular concern about the expulsion of Christians from communities that have had a Christian presence for 2,000 years and has demanded that they be allowed to return home in safety once the conflict settles.
Francis's three-day visit comes at a sensitive moment for Turkey, as it struggles to cope with 1.6 million refugees fleeing the IS advance in Syria and weighs how to respond to US calls to get more engaged with the international coalition fighting the extremists.
Turkey has accused the group of casting a shadow over Islam and has said Muslim countries have a duty to stand up against its radical views. But Ankara is still negotiating with the US over helping the coalition, pressing for a safe haven and a no-fly zone along the Syrian border with Turkey and demanding the coalition go after Syrian president Bashar Assad's regime.
Turkey has long been accused of turning a blind eye to IS fighters entering Syria from its territory in the hope that it would hasten Assad's downfall - charges it denies.
"Those who veer away from the message of Islam - which is a call for peace - and spread violence and savagery are in a state of rebellion against Allah no matter what they call themselves," Mr Gormez told the Pope in stressing Turkey's opposition to the fundamentalists.
He and President Recep Tayyip Erdogan both complained about rising Islamophobia in the West, with Mr Erdogan saying prejudice against Muslims was helping fuel radical Islamic groups like the IS in the Middle East and Boko Haram in Africa.
"Those who feel defeated, wronged, oppressed and abandoned ... can become open to being exploited by terror organisations," Mr Erdogan said.
The president said he hoped Francis's visit would strengthen ties between Christians and Muslims, but the Pope's arrival was met largely with indifference among Turkey's people, 99% of whom are Muslim.
The Pope was greeted at Ankara's Esenboga Airport by a line of Turkish dignitaries before heading to the mausoleum of the Turkish republic's founder, Mustafa Kemal Ataturk, where he laid a wreath.
"My wish is that Turkey, which is a natural bridge between the two continents, is not just a point of intersection, but at the same time a point where men and women belonging to all cultures, ethnicity and religion live together in dialogue," Francis wrote in a guest book at the mausoleum.
Beyond the geopolitical issues, the three-day visit will give Francis a chance to reach out to Turkey's tiny Christian community - less than 1% of Turks are Catholic - and visit with the spiritual leader of the world's Orthodox Christians, Ecumenical Patriarch Bartholomew I.
Francis will tour two of Istanbul's most impressive sites, the Haghia Sofia - the Byzantine church-turned-mosque that is now a museum - and the nearby Sultan Ahmet mosque, Turkey's most important place of Muslim worship. The Vatican's plans call for him to pause in the mosque for a moment of "reflection".
The Vatican added a speech to Francis's itinerary on Sunday at an event in which some Syrian refugees are expected to attend. The absence of any meeting with refugees had raised eyebrows given that Francis had met refugees in Jordan and in the Palestinian territories and has made welcoming refugees a major thrust of his papacy.
In his opening remarks to Mr Erdogan at his massive new presidential palace, Francis praised Turkey's welcome of refugees and said the international community had the "moral obligation" to help Ankara provide for them.
Security was tight: Turkish media reports said 2,700 police officers would be on duty during the Ankara leg of the trip, and that a court had issued an order allowing police to stop and search cars and carry out random identity checks on people along routes used by the pope.