A prominent Islamic scholar issued a religious ruling against terrorism and suicide bombings at a speech in London Tuesday.

Muhammad Tahir ul-Qadri, a leading scholar of Sufism, the tradition within Islam that focuses on peace and tolerance, isn't the first Islamic teacher to denounce acts of terrorism.

But Qadri's 600-page judgment, or fatwa, is among the harshest denouncements of the theological arguments used by militant groups like al-Qaeda.

"Whatever these terrorists are doing, it's not martyrdom," said Qadri on Tuesday.

U.K.-based anti-extremism think-tank the Quilliam Foundation, which sponsored the speech, called the Pakistani-born Qadri's fatwa "arguably the most comprehensive theological refutation of Islamist terrorism to date."

Suicide bombers destined for hell, Qadri says

Qadri condemned suicide bombers as destined for hell, a counter to the extremist promise of eternal paradise after death. Qadri said the fatwa outlaws suicide bombings "without any excuses, any pretexts, or exceptions."

He said he was compelled to issue the fatwa because of concerns about the radicalization of British Muslims at university campuses, most of whom are of Pakistani descent.

Nigerian Umar Farouk Abdul Mutallab, accused of trying to bomb a Detroit-bound plane on Christmas Day, studied at a London university until 2008.

Qadri is the founder of the international Minhaj-ul-Qur'an movement, which is mostly based in Pakistan, where he once served as an elected member of the national assembly and was a close associate of assassinated prime minister Benazir Bhutto.