Police last night warned Britain’s Christians to be on alert amid fears they could be targeted by ISIS jihadists.

Security was increased at the country’s 47,000 churches after an 84-year-old priest was beheaded by Muslim fanatics in France.

The killing in Normandy was the first known attack claimed by ISIS inside a church in the West after compiling a hitlist of places of Christian worship.

It comes as ISIS warned that London and Washington DC are next on the list of target cities, with images threatening major world capitals being posted online.

Adel Kermiche (pictured right and left, in 2011), 19, has been named as one of the two ISIS knifemen who stormed into a church in Normandy and cut the throat of an 84-year-old Catholic priest Jacques Hamel before being shot dead by police

A French policeman cordons off the area around the body of one of the two knifemen. Parisian prosecutor Francois Molins revealed that the pair were carrying a fake bomb with a timer, a handgun and knives during the attack and said they used nuns as human shields

Father Jacques Hamel had his throat cut in the attack that also left a nun critically injured. He was at the church because he was filling in for the local priest who was on holiday

Threat: ISIS warned Washington and London are next on the list of target cities. This image of the Statue of Liberty in flames was released on messaging app Telegram

This morning, French religious leaders joined forces to call for reinforced security after the attack.

Adel Kermiche, one of the two French teenagers killed by police after carrying out the morning slaughter – filmed on a mobile phone – told a friend two months ago: ‘I’m going to do a church.’

Last night counter-terror police in Britain disclosed they had ‘circulated specific advice’ to places of worship.

Deputy Assistant Commissioner Neil Basu said: ‘Following recent events in France, we are reiterating our protective security advice to Christian places of worship and have circulated specific advice today. We are also taking this opportunity to remind them to review their security arrangements as a precaution.

‘This is part of our ongoing work with faith organisations, as well as other sectors, to help ensure the safety and security of their staff, visitors and members.’ He said: ‘There is no specific intelligence relating to attacks against the Christian community in the UK.

‘However, as we have seen, Daesh and other terrorist groups have targeted Christian as well as Jewish and other faith groups in the West and beyond. While the threat from terrorism remains unchanged at severe we urge the public to be vigilant. Be alert and not alarmed and report any suspicious activity via the anti-Terrorist Hotline on 0800 789321. In an emergency always dial 999.’

There are around 5.4million Church members in the UK. In February last year, when a total of 17 people died in attacks by Islamist gunmen in Paris, including four men at a kosher supermarket, anti-terror police warned of ‘heightened concern’ of the risks to the Jewish community. It prompted an increase in patrols at schools and synagogues and in areas with large populations of the UK’s 263,000 Jews.

Police are still seeking the identity of the second attacker, and are continuing to carry out raids. Pictured, French officers and fire engines at the scene of the hostage taking

On another day of drama in France – which has suffered a string of atrocities since the Charlie Hebdo attacks in 2015:

Kermiche was revealed to be wearing an electronic tag after he was previously convicted of trying to join IS in Syria;

IS took responsibility for the murderous attack and said the knifemen were its ‘soldiers’;

The church was revealed to be on an IS ‘hitlist’ found after a previous plot to attack Catholic churches;

Former president Nicolas Sarkozy demanded ‘merciless’ action against terror suspects, calling for all Islamist terror suspects to be detained;

Politician Jean-Pierre Raffarin warned terrorists were trying to trigger ‘a war of religions’.

Father Jacques Hamel was killed yesterday morning after Kermiche, 19, and his young accomplice took him, two nuns and two early morning worshippers hostage.

During what turned into a siege, they chanted Arabic sermons before slitting the popular priest’s throat after he was forced to kneel. The pair were shot dead outside the church after leaving shouting ‘Allahu Akbar’.

French authorities say they have arrested a third man in connection with the attack. Armed police are pictured making an arrest at a house in Saint-Etienne-du-Rouvray

FROM KIND AND CARING TEENAGER, TO A RADICALISED PRIEST MURDERER Relatives and neighbours of priest killer Adel Kermiche last night spoke of their horror at his radicalisation by jihadists. Their comments came as it emerged he was a friend of another French jihadi, Maxime Hauchard, who has been linked to the beheading of Americans in Syria. Friends said teacher’s son Kermiche, 19, had previously enjoyed the life of a typical teenager. But last year he was convicted in France after attempting to join IS in Syria, which saw him issued an electronic tag and kept under curfew. The housing estate Kermiche lived in on the edge of St Etienne du Rouvray, near Rouen, has a significant proportion of north African Muslims. Kermiche’s parents are said to be Algerian-born. Last night a man identifying himself as Kermiche’s uncle said: ‘He was a good kid – he’d really been doing better after coming out of prison. ‘We can’t understand what happened, or how his life went down this road.’ A female friend of Kermiche, 18-year-old Imane El Fajri, said: ‘He was a very kind and adorable person. He must have been manipulated by people from outside, from ISIS. ‘This area is really calm, there are no problems here. His mother is a teacher. ‘He used to be at the local high school, and has been unemployed recently. He’s the kind of man who would always defuse arguments between his friends.’ Advertisement

Kermiche had twice been arrested for attempting to flee France to join IS in Syria, and had spent time in prison in both France and Switzerland.

He was supposed to be living with his parents in Saint-Etienne-du-Rouvray and being monitored with an electronic tag.

But under his bail conditions he was allowed to roam unsupervised between 8.30am and 12.30pm.

Security was raised at France’s 45,000 Catholic churches but safety concerns remain as it will be impossible to provide blanket protection.

The two killers, who shouted 'Allahu Akbar', were shot dead by police marksmen as they emerged from the building, which was later searched for bombs. Police later raided a house in the area and made an arrest

According to analysts at the SITE intelligence group, London is on the next list of cities ISIS wants to target next.

The terror group released images of the capital and other major world cities on the messaging app Telegram.

One shows the Statue of Liberty in New York on fire along with the words 'Washington soon'.

IS yesterday urged its followers to attack other French churches targeting what they called ‘Christian crusaders’.

The church of St Etienne du Rouvray was one of a number of Catholic churches on a terrorist ‘hit list’ found on a suspected IS extremist last April.

Sid Ahmed Ghlam was arrested in Paris as investigators believed he was planning ‘imminent attacks’. An arsenal of weapons was found in his car and at his flat.

Church leaders yesterday expressed outrage that a place of worship could become the scene of such a bloody attack. Pope Francis condemned the ‘barbarous killing’.

Meanwhile, French religious leaders today called for authorities to boost security at places of worship.

'We deeply desire that our places of worship are the subject of greater (security) focus, a sustained focus,' said French Muslim leader Dalil Boubakeur, after meeting with President Francois Hollande.

Hollande gathered with the leaders of the country's main religions a day after the killing.