Religious leaders in France have called for unity after a meeting with President Francois Hollande.
It follows the murder of a priest in Normandy by supporters of the so-called Islamic State group.
Paris Imam Dalil Boubakeur said France's Muslims must ensure clerics are better trained and called for reform of French Muslim institutions.
The Archbishop of Paris, Cardinal Andre Vingt-Trois, called on Catholics to "overcome hatred that comes in their heart" and not to "enter the game" of IS that "wants to set children of the same family in opposition to each other".
Muslim leaders say they don't want to "taint" Islam by burying Adel Kermiche who slit the throat of 85-year-old priest Father Jacques Hamel.
Islamic State's Amaq news agency released footage showing French attacker Abdel-Malik Nabir Petitjean urging Muslims to destroy the country.
The self-styled Islamic State has released a video of the French church attackers pledging allegiance to the group.