A nun who survived the gruesome terror attack that saw a priest slaughtered by ISIS butchers revealed how they were targeted for being Christians.

Sister Danielle was at the church in Saint-Etienne-du-Rouvray when the knife-wielding attackers stormed into the church, after morning mass at 9.45am.

One has been identified as a 19-year-old Frenchman Adel Kermiche, who was twice arrested for trying to join ISIS in Syria and was under police surveillance at the time of the savage attack.

Survivor: Sister Danielle, who was in the church in Saint-Etienne-du-Rouvray when two ISIS fighters stormed in waving guns, revealed how they were targeted for being Christian

Murdered: Father Jacques Hamel, 84, was slaughtered in the horrific assault, which saw the two knifemen film themselves as they cut his throat

Attacker: Frenchman Adel Kermiche (pictured in 2011), now 19, has been identified as one of the attackers. He was twice arrested for trying to join ISIS in Syria and was put under police surveillance

'It was fear, especially when they entered,' revealed Sister Danielle in an interview with the BBC.

'When I saw them I said to myself, "well, that's it. It's over". They were so motivated.

'They told me "you Christians, you kill us".'

The nun explained how 84-year-old Catholic priest Father Jacques Hamel had just celebrated his mass when the attackers 'took his place and started preaching in Arabic'.

She described how the pair 'forced him to kneel and told him not to move'.

Moments later, they murdered the priest, filming themselves as they cut his throat in a savage attack.

She added: 'Jacques loved all people regardless of religion. That is all I can say. A faithful priest, a priest who loved everybody, who loved much.'

As well as Father Jacques Hamel, they had taken four other hostages - two nuns and two parishioners.

The nun explained how 84-year-old Catholic priest Father Jacques Hamel had just celebrated his mass when the attackers 'took his place and started preaching in Arabic'

Probe: A policeman cordons the site next to the body of one of the two men who stormed a French church. The two attackers were shot after they emerged from the building shouting 'Allahu Akbar'

Aftermath: It is understood Father Jaques was only at the church because he was covering for the regular priest who was on holiday

Both the assailants were shot dead by police after they emerged from the church shouting 'Allahu Akbar', in the attack which was later claimed by ISIS.

It is understood Father Jaques was only at the church because he was covering for the regular priest who was on holiday.

A second nun, who wished to remain anonymous when talking to Le Figaro, said: 'They came suddenly. They took space. They spoke Arabic. I saw a knife.

'I left when they began to attack the Father Jacques. I do not even know if they realised that I was leaving.'

She said she was being supported by the critical incident stress management team and was waiting for news on her friend who was injured in the attack.

Despite having been released early from prison, Keriche's bail conditions allowed him to roam unsupervised between 8.30am and 12.30pm, leaving him free to murder the priest in the attack carried out between 9am and 11am.

Jailed: After being imprisoned for attempting to reach ISIS in Syria, Kermiche was released early and put under the care of his parents in Saint-Etienne-du-Rouvray, with an electronic tag on his ankle

Freedom: According to his bail conditions, Kermiche was also allowed to go out unsupervised between 8.30am and 12.30pm every day

In March 2015, while still a minor, Kermiche used his brother's ID to try to reach the terror group in Syria via Germany, but was arrested in Munich.

He was placed under judicial control with his parents, but after his 18th birthday again tried to return to the Middle East using an ID card belonging to a cousin.

Accompanied by two childhood friends, Kermiche headed to Switzerland overland and then took a plane to Turkey, hoping to cross the border into Syria.

Turkish police deported him back to Switzerland and, after being sent back to his hometown, he was tried and found guilty of 'associating with a terrorist enterprise' on May 22 2015.

After spending less than a year of his two-and-a-half-year sentence in prison, he was released on March 22 this year.

A prosecutor appealed the decision to release Kermiche, but he was released on bail on condition that he again stayed with his mother and father.

According to his bail conditions, Kermiche was also allowed to go out unsupervised between 8.30am and 12.30pm every day.

The revelation - made to the French TV news channel I-Tele - will cause further outrage in a country devastated by constant security failings.

Raids: A third man was arrested in connection with the attack after police raided a house near the church. He is believed to be a relative of one of the two attackers who were shot dead

Investigate: Wearing a white t-shirt and tracksuit bottoms, the teenager was led away by a special police team

It comes as it also emerged that the building was one of a number of Catholic churches on a terrorist 'hit list' found on a suspected ISIS extremist last April.

ISIS claimed responsibility for the attack in a statement published by its Aamaq news agency.

It said the killing was carried out by 'two soldiers of the Islamic State'.

It added the killing was in response to its calls to target countries of the US-led coalition which is fighting ISIS.

Paris prosecutor Francois Molins revealed the pair were carrying knives, fake explosives and a timer, and a backpack full of fake guns.

In a press conference, he said police are still seeking to identify the second attacker and raids were underway.

Describing both attackers as 'these appalling cowardly people', Mr Molins said police had tried to negotiate with them 'but couldn't get into the church because of the heavy locked door'.

He further revealed that the person who was seriously injured is no longer in a life-threatening condition.

A third man, a 16-year-old known as HB and believed to be the younger brother of someone wanted by police for trying to go to Syria or Iraq in 2015, was arrested at his home in Saint-Etienne-du-Rouvray following the attack.

Wearing a white T-shirt and tracksuit bottoms, he was led away in hancuffs by a special police team.

The officers were armed with military gear and assault rifles.

'War': ISIS claimed responsibility for the attack in a statement published by its Aamaq news agency. It said the killing was carried out by 'two soldiers of the Islamic State'

Upset: Pope Francis has expressed his 'pain and horror' at the incident with a spokesman saying the Pontiff was appalled by the 'barbaric killing' because it happened in a sacred place

Damage: French president Francois Hollande (pictured embracing the town's mayor Hubert Wulfranc) said France is 'at war' with ISIS while the terror group has claimed responsibility for the killing

French President Francois Hollande, visiting the scene of the attack, appealed for 'unity' in France, where political blame-trading has poisoned the aftermath of the Nice truck attack, the third major strike in the country in 18 months.

'The threat remains very high,' said Hollande. 'We are confronted with a group, Daesh, which has declared war on us. We have to wage war by every means, (but through) upholding the law, which is because we are a democracy.'

Pope Francis has expressed his 'pain and horror' at the incident with a spokesman saying the Pontiff was appalled by the 'barbaric killing' because it happened in a sacred place.

An Italian politician is urging the Pope to put the slain French priest on a fast track for sainthood.

Roberto Maroni, the president of the Lombard region, said in an appeal circulated on social media that 'Father Jacques is a martyr of faith' and requested that the pope 'immediately proclaim him St. Jacques.'

Shortly after the appeal, the hashtag #santosubito, which translates as 'saint immediately', began circulating on Twitter.

The canonisation process is a lengthy one involving two miracles attributed to the person's intercession, but in the case of a martyr only one miracle is needed, after beatification.

There must first be a declaration by the Vatican that the person indeed died for the faith.

She said she was being supported by the critical incident stress management team and was waiting for news on her friend who was injured in the attack

The Archbishop of Canterbury Justin Welby said: 'Evil attacks the weakest, denies truth and love, is defeated through Jesus Christ. Pray for France, for victims, for their communities.'

And Prime Minister Theresa May said Britain would 'stand shoulder to shoulder with France' as she spoke in Downing Street, adding a terrorist attack in the UK was 'highly likely'.

She said: 'What is necessary is for us all to work together, and stand shoulder to shoulder with France.

'We offer them every support we have in dealing with this issue and this threat that they, and the rest of us, are facing.

'But on one thing, I think, we are all absolutely clear, and that is the terrorists will not prevail.

'They are trying to destroy our way of life. They are trying to destroy our values. We have shared values and those values will win through and the terrorists will not win.'

The United States has also condemned the attack in the 'strongest possible terms'.

White House spokesman Ned Price said: 'France and the United States are committed to protecting religious liberty for all faiths.

'That commitment will not waver because of Tuesday's attack in the small northwestern town of Saint-Etienne-du-Rouvray.'

Mr Price also commended what he said was the 'quick and decisive response' by French law enforcement.

Trouble: The attack heaped pressure on Hollande to regain control of national security, with France already under a state of emergency 10 months ahead of a presidential election

But the attack heaped yet more pressure on President Hollande to regain control of national security, with France already under a state of emergency 10 months ahead of a presidential election in which he is widely expected to seek a second term.

The Normandy attack came less than two weeks after a 31-year-old Tunisian, Mohamed Lahouaiej Bouhlel, ploughed a rented lorry into a crowd of revellers in the French city of Nice, killing 85 people. Islamic State claimed that attack.

'Everything is being done to trigger a war of religions,' tweeted Jean-Pierre Raffarin, a former conservative prime minister who now heads the Senate's foreign affairs committee.

Mr Hollande visited the Normandy town with Interior Minister Bernard Cazeneuve, meeting survivors of the church attack and members of the emergency services.

Mr Cazeneuve has come under fire from conservative politicians for not doing enough to prevent the Nice attack, which prompted lawmakers to approve a six-month extension of emergency rule.

Ex-president Nicolas Sarkozy, expected to enter a conservative primary soon for next year's presidential election, jumped on the latest incident to accuse the Socialist government of being soft on terrorism.

'We must be merciless,' Mr Sarkozy said in a statement to reporters.

'The legal quibbling, precautions and pretexts for insufficient action are not acceptable.

'I demand that the government implement without delay the proposals we presented months ago. There is no more time to be wasted.'

Uproar: The centre-right opposition wants the government to put all Islamist suspects subject to a confidential security notice under administrative detention to avert potential attacks. Pictured, French far-right National Front leader Marine Le Pen (left) and ex-president Nicolas Sarkozy (right)

KILLING IS LATEST IN SPATE OF BLOODY ATTACKS ACROSS EUROPE Today's attack is the latest to hit Europe in what has been a year of bloodshed on the continent: July 24: Festival suicide bombing - A failed Syrian asylum seeker set off an explosive device near an open-air music festival in the southern city of Ansbach that killed himself and wounded a dozen others. The 27-year-old had spent time in a psychiatric facility, while the regional authorities said an there was 'likely' a jihadist motive for the attack. However a spokesman for the interior ministry later said there was as yet 'no credible evidence' of a link to Islamic extremism. July 24: Knife attack - A Syrian refugee was arrested after killing a Polish woman with a large kebab knife at a snack bar in the southwestern city of Reutlingen, in an incident police said did not bear the hallmarks of a 'terrorist attack' and was more likely a crime of passion. Three people were also injured in the assault, which ended when the 21-year-old assailant was deliberately struck by a BMW driver, believed to be the snack bar owner's son, trying to stop the man. People mourn in front of candles and flowers near the Olympia shopping mall in Munich, southern Germany, where an 18-year-old German-Iranian student ran amok on a shooting spree on July 22 July 22: Munich mall mass shooting - David Ali Sonboly, 18, shot dead nine people at a Munich shopping mall before turning the gun on himself, having spent a year planning the rampage. Police said that the German-Iranian was 'obsessed' with mass killers like Norwegian right-wing fanatic Anders Behring Breivik and had no links to the Islamic State group. July 18: Train axe attack - A 17-year-old migrant wielding an axe and a knife went on a rampage on a regional train, seriously injuring four members of a tourist family from Hong Kong and a German passer-by. ISIS group subsequently released a video purportedly featuring the assailant, named by media as Riaz Khan Ahmadzai, announcing he would carry out an 'operation' in Germany, and presenting himself as a 'soldier of the caliphate'. He is believed to have been Afghan or Pakistani. July 14: Tunisian Mohamed Lahouaiej Bouhlel ploughed a truck into a crowd of people celebrating Bastille Day in the French Riviera city of Nice, killing 84 people and injuring over 300. The Nice attack was the third major strike on France in 18 months and was claimed by ISIS. March 22: Suicide attacks claimed by ISIS kill 32 people and wound more than 300 at the Brussels airport and Maelbeek metro station, near European Union offices. They appear to have been carried out by members of the same cell that committed attacks in Paris four months earlier. November 13, 2015: Coordinated suicide attacks in Paris kill 130 people and wound more than 350 at the Bataclan concert hall, cafes and the national stadium. ISIS claims responsibility for the attacks. Advertisement

The centre-right opposition wants the government to put all Islamist suspects subject to a confidential security notice under administrative detention to avert potential attacks.

Far-right National Front leader Marine Le Pen, also expected to run for the presidency, said both major parties had failed on security.

'All those who have governed us for 30 years bear an immense responsibility. It's revolting to watch them bickering.' she said on Twitter.

Mr Hollande insisted that the government must stick to the rule of law, which was what the hallmark of a democracy.

French security services have been regularly criticised for the way they allow known terrorists their freedom after being found guilty of crimes.