A Muslim group has opened what it calls the UK's first summer camp against terrorism.
The three-day event in Coventry is expected to see more than 1,000 young Muslims at sessions teaching religious arguments to use against extremists.
The event has been organised by the Minhaj ul-Quran to promote a fatwa, or religious ruling, against terrorism by its leader Dr Muhammad Tahir ul-Qadri.
Dr Qadri launched the fatwa in London in March.
Opening the summer camp, Dr Qadri told the audience - predominantly made up of British Muslims - to reject al-Qaeda and its "cancer" that was spreading through their faith.
He told them to embrace being British and do all that they could to build a safe and secure society by using sound theological arguments to confront any extremists that they meet.
The populist Pakistani cleric's 600-page theological study is billed by his followers as the most comprehensive and clear denunciation of the arguments deployed by jihadists to justify violence including suicide bombings and the targeting of civilians.
The summer camp at Warwick University will concentrate on this document and will include debates and talks.
Participants are being asked to join "a spiritual war" against al-Qaeda's recruiters.
Minhaj ul-Quran, the international organisation set up by the cleric, argues that many traditional Muslim organisations have been too timid in taking on jihadist ideology, unintentionally leaving youngsters bewildered and susceptible to brainwashing.
The organisation, which is expanding in the UK, argues that there has to be a more public stand against extremism, underpinned by a sound understanding of what Islam says about violence.
Speaking ahead of the event's launch, the cleric said: "I have announced an intellectual and spiritual war against extremism and terrorism. I believe this is the time for moderate Islamic scholars who believe in peace to stand up."
"I feel it is my duty to save the younger generation from radicalisation and wave of terroristic recruitment in the West."
Dr Qadri, now based in Canada, is not the first preacher to speak out against terrorism - but his followers hope his fatwa will become the most influential document in circulation.
The UK's largest umbrella body, the Muslim Council of Britain (MCB), has repeatedly called together scholars and preachers to denounce extremism.
But critics say that some of the MCB's leaders have no moral authority to preach to youngsters because they have been equivocal about violence in the Middle East.