A top British prosecutor has warned that hundreds of teenagers in the U.K. are in danger of being radicalized by the Islamic State group, because of the militants' savvy propaganda tactics. The campaign to market the group, also known as ISIS or ISIL, has left many young Muslims vulnerable to “jihadimania,” said Nazir Afzal in an interview with the Guardian published on Sunday.

“The boys want to be like them and the girls want to be with them,” Afzal, who is a Muslim, said. “That’s what they used to say about the Beatles and more recently One Direction and Justin Bieber. The propaganda the terrorists put out is akin to marketing, and too many of our teenagers are falling for the image.”

Among the nearly 3,400 recruits that are estimated to have left Western countries to join Islamic State fighters in Syria and Iraq are around 600 young British Muslims, most notably including “Jihadi John.” The militant, who has since been identified as British-Kuwaiti dual national Mohammed Emwazi, is purported to have been the executioner featured in the group’s infamous hostage-beheading videos.

The steady flow of young Muslims to the Islamic State has deeply unnerved Western security agencies, which have been struggling to find ways to counter the group’s sophisticated online recruitment machine. With a reported $2 billion at its disposal, the Islamic State has been able to invest in slickly produced propaganda videos that extol the virtues of living in the territory under its control. The group has also employed social media platforms to spread its message and to aid in its recruitment, an effort that has also seen success among young women and girls.

One female former extremist claimed recently that ISIS recruiters targeted young girls by using imagery featuring “attractive” jihadists. "As a teenager I wanted to get my piece of eye candy and I'd take a good look, and all the YouTube videos, for some reason, they [the militants] were all really, really attractive,” said the woman, who goes by the pseudonym Ayesha, in an interview with BBC Newsnight last month. "It was like, get with him before he dies. And then when he dies as a martyr you'll join him in heaven."

Three British teenage girls gained international attention in February after fleeing London to join ISIS in Syria. The girls are thought to have been recruited by Aqsa Mahmood, a 20-year-old woman from Glasgow who gained notoriety for encouraging on her blog young women to travel to Syria and marry jihadi fighters. Mahmood’s recruiting efforts and active social media presence have made her a poster girl for ISIS.

The success of these efforts has raised concerns among Muslims in the UK, including Afzal, who argued that the best way to counter the threat was by mobilizing an army of young British Muslims to turn would-be ISIS fighters back from the brink.

“The reality is that [ISIS] are no more than narcissistic, murderous cowboys. We need to stand up and say that very, very clearly, rather than allow kids to be drawn to them like the equivalent of pop idols,” he said. “Thousands of young people and professionals can be encouraged to show these potential radicals what their lives could be. They don’t want to hear from men with long beards, they don’t want to hear from faith leaders. They want to hear from women and from young professionals who can show them there is hope if they stay in education and make a contribution locally.”

Afzal, who just stepped down as the head of the Crown Prosecution Service in northwest London, said he fears that another major terror attack in the style of London’s July 2005 subway bombings could happen unless Britain focused on introducing a community-led approach to counter-terrorism.