* Ex-president Sarkozy renews assault on security record
* Interior minister says jailing suspects counterproductive
President Francois Hollande displayed interfaith solidarity with France's religious leaders on Wednesday after two Islamist militants killed a Roman Catholic priest in a church, igniting fierce political criticism of the government's security record.
One of the assailants was a known would-be jihadist awaiting trial under supposedly tight surveillance, a revelation that raised pressure over the Socialist government's response to a wave of attacks claimed by Islamic State since early in 2015.
"We cannot allow ourselves to be dragged into the politics of Daech (Islamic State), which wants to set the children of the same family against each other," the Archbishop of Paris, Cardinal André Vingt-Trois, told journalists after the meeting at the Elysee presidential palace.
He was flanked by representatives of other Christian denominations as well as Jewish, Muslim and Buddhist leaders.
Hollande and his ministers were already under fire from conservative opponents over the policing of Bastille Day celebrations in the Riviera city of Nice in which 84 people died when a delivery man drove a heavy truck at revellers.
Former president Nicolas Sarkozy, who is expected to enter a conservative primary for next year's presidential election, stepped up his attack on Hollande's record since the first major attack against satirical magazine Charlie Hebdo last year.
"All this violence and barbarism has paralysed the French left since January 2015," Sarkozy told Le Monde newspaper. "It has lost its bearings and is clinging to a mindset that is out of touch with reality."
Sarkozy has called for the detention or electronic tagging of all suspected Islamist militants, even if they have committed no offence. France's internal security service has confidential "S files" on some 10,500 suspected jihadists.
Interior Minister Bernard Cazeneuve rejected Sarkozy's proposal, saying that to jail them would be unconstitutional and in any case could be counterproductive.
"What has enabled France to break up a large number of terrorist networks is keeping these people under 'S file' surveillance, which allows intelligence services to work without these individuals being aware," he said on Europe 1 radio.
A wreath of flowers is displayed in front of the church a day after a hostage-taking in Saint-Etienne-du-Rouvray.
The chairman of France's conference of religious faiths, Protestant community leader Francois Clavairoly, said after the talks with Hollande that it was impossible to protect every place of worship in the country.
"Everyone has to take responsibility, use best practice and keep an eye open," he said.
Death at the altar
Tuesday's attackers interrupted a church service, forced the 85-year-old priest to his knees at the altar and slit his throat. As they came out of the church hiding behind three hostages and shouting "Allahu akbar" ("God is Greatest"), they were shot and killed by police.
The knifemen arrived during morning mass in Saint-Etienne-du-Rouvray, a working-class town near Rouen, northwest of Paris, where Father Jacques Hamel had been celebrating mass. One of the hostages was badly wounded during the attack.
Islamic State said on its news agency that its "soldiers" carried out the attack. It has prioritised targeting France, which has been bombing the group's bases in Iraq and Syria as part of a US-led international coalition.
Police said they arrested a 16-year-old local youth after the incident but Cazeneuve said on Wednesday he did not appear to be linked to the church attack.
One of the attackers, 19-year-old Adel Kermiche, was a local man who was known to intelligence services after his failed bids to reach Syria to wage jihad.
Kermiche first tried to travel to Syria in March 2015 but was arrested in Germany. Upon his return to France he was placed under surveillance and barred from leaving his local area.
Less than two months later, Kermiche slipped away and was intercepted in Turkey making his way towards Syria again.
He was sent back to France and detained until late March this year when he was released on bail pending trial for alleged membership of a terrorist organisation. He had to wear an electronic tag, surrender his passport and was only allowed to leave his parents' home for a few hours a day.
Kermiche's tag did not send an alarm because the attack took place during the four hour period when he was allowed out.
According to the justice ministry, there are just 13 terrorism suspects and people convicted of terrorist links wearing such tags. Seven are on pre-trial bail. The other six have been convicted but wear the electronic bracelet instead of serving a full jail term.
France was already in a state of shock less than two weeks after the Nice truck attack. In November, 130 people died in shooting and suicide bombings in and around Paris.
In March, three Islamist militants linked to the Paris attackers killed 32 people in suicide attacks on Brussels airport and a metro station in the Belgian capital.
Since the Bastille Day killings in Nice, there has been a spate of attacks in Germany too.
