James Foley beheading: Hunt is now on to find the home-grown jihad recruits
Even in Northern Ireland a number of Islamic extremists have been identified
David Cameron has said the war against Islamic extremism will mean taking them on in the UK as well as fighting them abroad after a British jihadist beheaded a US journalist.
James Foley was decapitated by a masked militant with a London accent referred to as 'John' in chilling footage described by the Prime Minister as "brutal and barbaric".
International attention is now focusing on the growing threat posed by Western converts to the cause of Islamic terror.
Even in Northern Ireland, where loyalist and republican paramilitaries hold sway, a number of Islamic extremists have been identified.
Earlier this year it was reported that Londonderry man Eamon Bradley had joined a Syrian rebel group. The Creggan native is believed to have joined militants fighting in a civil war against the regime of President Bashar Assad.
And the world's most wanted female terror suspect– 'White Widow' Samantha Lewthwaite – hails from Banbridge. It has also emerged that gardai have identified 30 jihadists using the Republic as a base.
The Prime Minister cut short his second summer holiday to return to Downing Street and oversee the response after the horrific video was posted online.
Mr Cameron said people must show “patience and resolve in fighting this, here at home in the UK and in other parts of the world where countries have been affected”.
“It is a battle we have to fight in our own country, it is a battle with allies using everything that we have — our aid, our diplomacy, and yes on occasions our military powers — that we have to fight, whether it is dealing with this problem in Somalia, in Mali, in Afghanistan, in Iraq, in Syria, because as much as we want to focus on keeping ourselves safe here at home, and that is my focus, what happens in these other far-flung places can come back and cause huge harm here too.”
Last month the PSNI searched the home of Eamon Bradley and removed mobile phones after it emerged that the Derry man was involved in the civil war in Syria. Pictures later emerged of Bradley with an AK-47 assault rifle and dressed in combat gear.
Bradley — who converted to Islam four years ago — told his family via text that he has completed his guerrilla training and is prepared to be a martyr if he has to.
In 2004, former UVF killer George Armstrong became Ulster's first loyalist terrorist to convert to Islam when he became a Muslim inside his prison cell. He pledged his loyalty to Allah while serving time in HMP Lowdham Grange, Nottinghamshire, over a pub assault.
Bangor fraudster Mark Townley is now using the name Ashraf Islam following a dramatic decision to become a Muslim when he fled Northern Ireland as the net closed in on his latest scam.
He was jailed in February for a plot to kill Prince Harry.
Murder suspect Kieran McLaughlin, who is accused of the shotgun murder of Londonderry man Barry McCrory last year, turned to the Muslim faith while in an isolation unit in Maghaberry prison.
Meanwhile, Kenyan detectives are struggling to find 30-year-old fugitive Samantha Lewthwaite, who has been on the run for more than two years.
The mother-of-four and Muslim convert from Banbridge is the widow of Jermaine Lindsay, one of the 7/7 suicide bombers who died along with 26 passengers on a Tube train in 2005.
Other suspected extremists have moved here. In 2004, a Filipino man described as an Islamic radical was said to be “lying low” in Belfast when he was arrested, and one of the Algerian masterminds of an al-Qaida terror plot in London came to Dublin in 1997, where he was reportedly radicalised by a cleric he met in Belfast.