Two men attacked a church near Rouen, France, on Tuesday, taking several hostages and killing an 86-year-old priest before they were shot to death by police.
The self-described Islamic State, through the group's Amaq news agency, claimed responsibility for the attack in the small town of Saint-Étienne-du-Rouvray.
The men were armed with knives and took five hostages — Father Jacques Hamel, two nuns and two parishioners, The Guardian reports.
The attackers killed Hamel by slitting his throat and they seriously injured another hostage. Interior Ministry spokesman Pierre-Henry Brandet said the wounded person is "between life and death."
The three other hostages were rescued by police, The Associated Press reports.
"It was the first known attack inside a French church in recent times," the wire service writes:
"Islamic State extremists have urged followers to attack French churches and the group is believed to have planned at least one church attack earlier.
"[Tuesday's] attack once again demonstrates the challenge of combating the threat. French authorities increased security at churches, synagogues, mosques and other places of worship after attacks in Paris last year, but ensuring constant, blanket security is difficult in a country with a church in every town and village."
The AP reports that one of the men was known to police, according to a regional Muslim leader and an anonymous police official. Both sources suggested the known attacker had been monitored by authorities for some time.
Pope Francis and the Archbishop of Rouen have condemned and mourned the attack.
The Vatican called the killing of Hamel "barbaric."
"I cry out to God, with all men of good will. And I invite all non-believers to unite with this cry," Archbishop Dominique Lebrun wrote, according to the AP. "The Catholic Church has no other arms besides prayer and fraternity between men."
French President Francois Hollande called the killing and hostage-taking a "vile terrorist attack" and reiterated France's commitment to battling the Islamic State.
"We are put to the test yet again," Hollande said, according to Reuters.
ISIS also claimed responsibility for the truck attack in Nice on July 14, which killed 84 people, as well as the Charlie Hebdo and November attacks in Paris last year.