ROUEN, France (AP) — The sister of the French priest slain by extremists appealed at his funeral on Tuesday for all faiths to work together for peace.

"Let's learn to live together, let's be workers for peace," Roselyne Hamel told an estimated 1,700 people gathered in Rouen cathedral in western France for the funeral Mass for her brother, Father Jacques Hamel. The 85-year-old priest was murdered last week at a church in the nearby town of Saint-Etienne-du-Rouvray.

Interior Minister Bernard Cazeneuve was among those attending the Mass in the sumptuous Gothic cathedral, which dates from the 12th century. Hundreds of people watched the ceremony on a big screen outside the cathedral, under constant rain.

Archbishop Dominique Lebrun, celebrating the Mass, extended thanks to Catholics attending the service but also to "believers of other religious faiths, in particular the Jewish community and the Muslim community, very affected and already decided to unite for: 'Never again.'"

Lebrun invited people to return to churches on Aug. 15, the day celebrating the Assumption of Mary, to express that "violence will not take over in their hearts."

On Sunday, dozens of Muslims in France and Italy attended Catholic Masses as a gesture of interfaith solidarity following the attack on the priest.

The Islamic State group claimed responsibility for the attack, in which the priest, two nuns and an elderly couple were held hostage before the assailants slashed the priest's throat and seriously wounded the other man. Another nun at the Mass slipped away and raised the alarm, and police shot to death both attackers as they left the church.

Tuesday's ceremony was organized under tight security, and burial was to be held privately.

Corbet contributed from Paris.