Is Libyan beach executioner an American recruit? Experts claim ISIS jihadi spoke with U.S. accent picked up by spending a 'significant amount of time' in the country
The militant, who spoke English with a U.S. accent, appeared in a horrific video on Sunday showing the beheadings of a group of Coptic Christians on a beach in Libya.
Brandishing a knife, he declares: 'All crusaders... the sea you have hidden Sheikh Osama bin Laden's body in, we swear to Allah we will mix it with your blood.'
The men are then forced to lie face-down before they are beheaded simultaneously.
U.S. officials are understood to be analysing the militant's facial features and speech patterns as has been done in the hunt for the British executioner known as Jihadi John, who has appeared in a number of beheading videos in Syria.
Professor Erik Thomas, a linguistics expert at North Carolina State University, believes he 'sounds like an American' with some Arabic influence, based on some of word pronunciations.
Another U.S. specialist, who asked not to be named told ABC News that he may be a native Arabic speaker who learned English by spending 'a significant amount of time' in America.
The suggestion he may have been radicalised in the U.S. comes as the Obama administration faced heavy criticism for suggesting that defeating ISIS requires more of a jobs program for terrorists than a sophisticated approach to killing them.
State Department spokesman Marie Harf said Monday night on MSNBC that 'we cannot win this war by killing them, we cannot kill our way out of this war.'
Instead, she said, the administration should 'go after the root causes that leads people to join these groups' – including 'lack of opportunity for jobs.'
'We can work with countries around the world to help improve their governance,' Harf insisted. 'We can help them build their economies so they can have job opportunities for these people.'
The embarrassing gaffe aired as the White House attracted new criticism for papering over religious aspects of a mass-beheading of Coptic Christians by the ISIS terror army.
White House Press Secretary Josh Earnest issued a 192-word reaction condemning the brutal killings as 'despicable' and 'cowardly' but made no mention of the religion of the killers or their victims.
The words 'Christian,' 'Islam' and 'Muslim.' were not included in Earnest's statement.
A CNN/ORC poll found 57 per cent of Americans disapprove of how President Obama is handling the threat posed by ISIS.
Even among Democrats, 46 per cent say America's battle with ISIS is going badly.
Public approval of the administration's anti-ISIS efforts has slipped by 8 percentage points since September.
Part of that slide may be due to the State Department's focus on what conservatives deride as 'hashtag diplomacy' – a program of pushback through social media designed to strip away ISIS's glamourous appeal to would-be jihadis.
Vice President Joe Biden has also called for immigrants to be fully included in the fabric of American society to prevent violent ideologies from taking root at home as he opened a White House summit on countering extremism and radicalisation.
Joining local elected officials, community leaders and religious figures, Biden portrayed the U.S. as far better positioned than Europe, thanks to what he called America's successful record at cultural integration. He said societies must offer immigrants an 'affirmative alternative' to extremism, cautioning that military force alone could not address the threat.
Across the Atlantic, deadly terrorist attacks in France, Belgium and Denmark have left Europeans feeling vulnerable to the type of violent ideology promoted by the Islamic State group and once thought to be confined mostly to the Middle East and North Africa.
'National security flows from a sense of community,' Biden said, adding that the most important lesson the U.S. can learn is that 'inclusion counts.'
The White House has sought to use the three-day conference in Washington to stir a sense of urgency about the challenge of preventing home-grown terrorism and the radicalization and recruitment of Americans, particularly disaffected young people.
Yet it comes as the Obama administration has struggled to match its stated strategy for fighting IS and other Islamic extremist groups with the realities on the ground in Libya, Yemen and other Mideast hotspots.
On Wednesday, President Barack Obama was to address a gathering at the White House examining the response from U.S. cities, then speak at the State Department on Thursday at a gathering of representatives from roughly 60 countries.
Britain, Jordan, Egypt, the United Arab Emirates, Kuwait and France are expected to attend.
Global concerns that the Islamic State is drawing interest and support from communities far away from Iraq and Syria have only grown in recent days.
As well as Egypt and Libya, Denmark is reeling from a weekend shooting spree by a 22-year-old gunman that authorities believe may have been radicalized in prison.
Biden, in his remarks, held up Boston, Los Angeles and Minneapolis as examples of communities moving ahead with programs to counter extremism locally.
He said the goal was to bring together broad coalitions of community leaders so that all Americans - and particularly Muslims - would feel like 'we see them.'
'We haven't always gotten it right,' Biden said. 'But we have a lot of experience integrating communities into the American system, the American dream.'