ISTANBUL, Turkey (AP) – Pope Benedict XVI began his pilgrimage among Turkey’s tiny Christian communities Wednesday by paying homage to an Italian priest slain during Islamic protests and expressing sympathy for the pressures facing religious minorities in the Muslim world.

The messages – made at one of the holiest Christian sites in Turkey – could set the tone for the remainder of Benedict’s first papal trip to a Muslim nation as he tries to strengthen bonds with the spiritual leader of the world’s Orthodox Christians.

The pope is expected to sharpen his calls for what the Vatican calls “reciprocity” – that Muslim demands for greater respect in the West must be matched by increased tolerance and freedom for Christians in Islamic nations.

But too much pressure by the Roman Catholic pontiff could risk new friction with Muslims after broad gestures of goodwill in the opening hours of the trip Tuesday that sought to ease simmering Muslim anger over the pope’s remarks on violence and the Prophet Muhammad.

A statement claiming to be from al-Qaida in Iraq denounced the pope’s visit as part of a “crusader campaign” against Islam and an attempt to “extinguish the burning ember of Islam” in Turkey. Vatican spokesman the Rev. Federico Lombardi said the declaration – posted on several Islamic militant Web sites – shows the need for faiths to fight “violence in the name of God.”

He said “neither the pope nor his entourage are worried.”

The pope’s deepening ties with Ecumenical Patriarch Bartholomew I – called the “first among equals” of the Orthodox leaders – also is watched with suspicion in Turkey as a possible challenge to state-imposed limits on Christian minorities and others. Benedict has declared a “fundamental” commitment to try to heal rifts between the two ancient branches of Christianity, which split nearly 1,000 years ago over disputes including papal authority.

At Bartholemew’s walled compound in Istanbul, the pope stood amid black-robbed Orthodox clerics and urged both sides “to work for full unity of Catholics and Orthodox.”

The pope began the day at the ruins of a small stone home at the end of a dirt road near the Aegean Sea – the site where the Virgin Mary is thought to have spent her last years.

At an outdoor Mass attended by 250 invited guests, the pope noted the challenges facing the “little flock” of Christians in Turkey.

“I have wanted to convey my personal love and spiritual closeness, together with that of the universal church, to the Christian community here in Turkey, a small minority which faces many challenges and difficulties daily,” the pope said.

At times, he smiled and showed flashes of the pastoral flair of his predecessor, John Paul II, in one of the most intimate papal gatherings since John Paul’s trip to remote Mount Sinai during a trip to Egypt in 2000.

Benedict went on to honor the memory of a Catholic priest who was slain in Turkey amid Muslim anger over the publication in European newspapers of caricatures of Muhammad.

“Let us sing joyfully, even when we’re tested by difficulties and dangers as we have learned from the fine witness given by the Rev. Andrea Santoro, whom I am pleased to recall in this celebration,” said Benedict, who later walked amid the crowd as they reached to touch his gold-and-white robes and cried “Viva il Papa” and “Benedetto,” his name in Italian.

In February, a Turkish teenager shot the Italian priest as he knelt in prayer in his church in the Black Sea port of Trabzon. The attack was believed to have been linked to outrage over the cartoons. Two other Catholic priests were attacked this year in Turkey, where Christians have often complained of discrimination and persecution.

On Tuesday, the pope urged religious leaders of all faiths to “utterly refuse” to support any form of violence in the name of faith. He also said religious freedom was an essential element of democratic values.

He sought a careful balance as he held out a hand of friendship and brotherhood to Muslims, and expressed support for measures that Turkey has taken in its campaign to join the European Union.

But winning over Turkish sentiments may be easy compared with the complexities ahead.

The legacy of Christianity in Turkey is a tangle of historical and religious sensitivities.

Turkish armies captured the Byzantine capital Constantinople – now Istanbul – in 1453 to begin a steady decline for Christians, who had maintained communities in Asia Minor since the time of the Apostles.

As the Ottoman Empire collapsed in the early 20th century, large numbers of Armenian Christians perished in mass expulsions and fighting. Turkey vehemently denies that it committed genocide against Armenians, though many nations have classified the World War I-era killings as such.

Later, in the 1920s, Turkey and Greece carried out a massive population exchange under the treaty that established modern Turkey, with hundreds of thousands of Greek Orthodox sent to Greece and smaller numbers of Muslims going the other way.

Bartholomew heads the remnants of the Greek community in Istanbul that now number no more than 2,000 among about 90,000 Christians in Turkey.

But they still represent a powerful symbolic presence for the world’s more than 250 million Orthodox, which often denounce Turkey for placing obstacles in the way of Bartholomew and his clerics.

Turkey refuses to acknowledge the “ecumenical,” or universal, title of the patriarch and instead considers him only the head of the local Greek Orthodox community. The Turkish worry is that granting wider status to the patriarch could undermine the idea of a single Turkish nationality – a pillar of the nation’s secular system – and inspire demands for special recognition by minorities including Kurds and Muslim groups such as Sufis and Alawites, considered a branch of Shiite Islam.

Now, Turkish officials are concerned the papal visit and support for Christian minorities could embolden Bartholomew to press Turkey for concessions, including return of confiscated property and the reopening of a Greek Orthodox seminary that closed more than two decades ago after authorities blocked new students. The EU has also pushed Turkey for greater religious openness to help its faltering bid for membership.

“Against the backdrop of universal peace, the yearning for full communion and concord between all Christians becomes even more profound and intense,” he said at the ancient Christian site.

Nestling on a mountain in woods between the ancient city of Ephesus and the town of Selcuk, near the Aegean coast, St. John the Apostle is believed to have brought the Virgin Mary to the house to care for her after Jesus’ death. Another belief maintains that the Virgin Mary died in Jerusalem.

The ruins of the house, whose earliest foundations date to the first century, have become a popular place of pilgrimage for both Muslims and Christians since the 1950s.

A chapel was built over the ruins, and some believe in the healing powers of both the chapel and waters flowing from a nearby spring.

Of Turkey’s 70 million people, some 65,000 are Armenian Orthodox Christians, 20,000 are Roman Catholic and 3,500 are Protestant, mostly converts from Islam. Another 23,000 are Jewish.