Muslims across France were invited to participate in Catholic ceremonies on Sunday to mourn a priest whose murder by Militant teenagers sparked fears of religious tension.
Masses will be celebrated across the country in honour of octogenarian Father Jacques Hamel, whose throat was cut in his church on Tuesday in the latest militant attack on France.
"We are all Catholics of France," said Anouar Kbibech, the head of the French Muslim council CFCM, in an expression of togetherness in the wake of the attack.
The council said that by attending Sunday's Catholic services, Muslims would show their "solidarity and compassion" over the murder.
Two 19-year-olds, Adel Kermiche and Abdel Malik Petitjean, carried out the attack, which was claimed by the Islamic State group. Police shot both of them dead following a hostage drama.
Prime Minister Manuel Valls called Sunday for a new "pact" with the Muslim community in France, Europe's largest with around five million members.
Valls has previously urged a temporary ban on the foreign financing of mosques in France and called for imams to be trained domestically.
The prime minister and his interior minister, Bernard Cazeneuve, have faced mounting calls to resign over alleged security lapses after it emerged that both attackers were known to the security services.
Police were still questioning Petitjean's cousin as well as a Syrian refugee, after a photocopy of his passport was found at Kermiche's house.
A source close to the enquiry said that a 17-year-old, who had tried to travel to Syria with Kermiche, was arrested in Geneva and sent back to France just a few days before the attack.
However, "nothing suggests he was in any way implicated in the attack" at this stage, the source added.
Sunday's religious ceremonies follow a "brotherhood march" in the southeastern city of Lyon, supported by a regional Muslim council and a Catholic group.
Hundreds of people marched in silence, as mourners at the front of the crowd carried banners that read: "This is not a religious war" and "We are all brothers and sisters".
"We think it is crucial to leave no room for resignation, resentment or fear, and to take a stand for togetherness," Abdelkader Bendidi, who heads the regional Muslim council, said in a statement.
"Let's not give the agents of terror a second victory by giving in to hate," said Azzedine Gaci, a local imam.
Foucauld Giuliani, of a Catholic group, stressed meanwhile that "these attacks won't divide us. Instead, they will unite us around one idea: reconciliation."