PARIS — Two attackers invaded a church today during morning Mass near the Normandy city of Rouen, killing an 84-year-old priest by slitting his throat and taking hostages before being shot and killed by police, French officials said.

Another person inside the church was seriously injured and is hovering between life and death, Interior Ministry spokesman Pierre-Henry Brandet said.

Police managed to rescue three other people inside the church in the small northwestern town of Saint-Etienne-du-Rouvray, Brandet told reporters, and the two attackers were killed outside the church.

The identities of the attackers and motive for the attack are unclear, according to a French security official who was not authorized to be publicly named.

Brandet said the RAID special intervention force was searching the perimeter of the church ahead of entering for possible explosives and terrorism investigators had been summoned.

“The investigations are ongoing. There are still unknowns,” Brandet said. “There are dogs, explosive detectors and bomb disposal services and as long as there are still unknowns, the judicial police cannot get inside the site. It’s a dramatic situation.”

It was the first known attack inside a French church in recent times. One was targeted last year, but the attack never was carried out. The antiterrorism division of the Paris prosecutor’s office immediately opened an investigation.

French President Francois Hollande traveled to the town. Interior Minister Bernard Cazeneuve was also visiting.

Dominique Lebrun, the archbishop of Rouen, confirmed the death of 84-year-old Rev. Jacques Hamel.

“I cry out to God, with all men of good will. And I invite all nonbelievers to unite with this cry,” Lebrun wrote in a statement.