ROME – In the wake of a shooting at a Catholic Church in an Istanbul neighborhood Sunday that left one person dead, responsibility for which has been claimed by ISIS, fear is once again on the rise among Turkey’s embattled Christian minority.

“We Christians, here as in many parts of the world, must be cautious,” said Father Alessandro Amprino, an Italian priest who serves in Turkey in the Archdiocese of Izmir.

Sunday’s violence occurred at the Church of St. Mary in the Sariyer district of Istanbul, a traditional working-class zone of the sprawling Turkish city. Two gunmen wearing black balaclavas entered the church during Mass shortly before noon local time, killing a Turkish citizen named Tuncer Cihan.

According to a relative of the victim who spoke to Turkish media, Cihan was a mentally disabled individual who’d been invited to the Mass by relatives, and in all likelihood was not specifically targeted by the assailants. Video footage from inside the church showed the gunmen firing at Cihan when he walked in front of them, and then leaving the church almost immediately afterwards.

The Islamic State quickly claimed responsibility for the shooting, using a Telegram account to assert that it came in response to a call by the group’s leaders to target Jews and Christians.

After a brief manhunt, Turkish authorities arrested two suspects in the assault, saying one was from Tajikistan and the other from Russia, and that both have ties to ISIS.

Pope Francis conveyed his condolences over the attack during his traditional noontime Angelus address Sunday.

“I express my closeness to the community of Saint Mary Church in Istanbul that suffered an armed attack during mass that caused one death,” he said.

Although Turkish President Recep Tayyip Erdoğan made a phone call to the church’s pastor and vowed that “all necessary measures” would be taken to bring the perpetrators to justice, for many Turkish Christians the episode nonetheless called to mind other past atrocities.

In January 2006, a Protestant church leader named Kamil Kiroglu, a Muslim convert to Christianity, was beaten unconscious by a gang of young men shouting “Deny Jesus or we will kill you now!” and “We don’t want Christians in this country!”

One month later, an Italian Catholic missionary priest named Father Andrea Santoro was gunned down by a 16-year-old Muslim boy in the small city of Trazbon shouting “Allahu Akbar,” reportedly in retaliation for Danish cartoons satirizing Muhammad. Three other Catholic priests in Turkey were assaulted shortly after Santoro’s death, though none were killed.

Ironically, Santoro’s bishop at the time, a Capuchin missionary named Luigi Padovese, warned that the priest’s murder was part of a rising tide of anti-Christian threats in Turkey. Four years later, Padovese himself was killed by his driver and longtime aide, Murat Altun, who stabbed the cleric multiple times and then beheaded him.

Turkey officially is a secular state, but roughly 97 percent of the population is Muslim and the small pockets of religious minorities in the country routinely complain of harassment and marginalization, especially from ultra-nationalists who see Christians above all as agents of the west, often accusing them of being in league with Kurdish separatists.

Although the Christian population in Turkey had dwindled to roughly 150,000 prior to the Russian invasion of Ukraine, the recent arrival of tens of thousands of Russian and Ukrainian refugees has boosted the country’s Orthodox community.

Sunday’s attack comes ahead of local elections in Turkey set for March 31, and politicians both from Erdoğan’s governing Justice and Development Party and various opposition factions expressed condemnations of the violence.

“Any attack on a single human being, let alone our Christian citizens, is treason,” said Cemal Enginyurt, an Istanbul MP from the opposition Democrat Party.