In early 2003, Osama bin Laden sought and received from a radical Saudi cleric a religious ruling, or fatwa, that the use of a nuclear bomb against US civilians would be permissible under Islamic law—indeed mandatory—if it were the only means to stop US actions against Muslims. “If a bomb that killed 10 million of them and burned as much of their land as they have burned Muslims’ land were dropped on them, it would be permissible,” the ruling held. Also in 2003, proceedings in a Russian criminal case revealed that a Russian businessman had been offering $750,000 for stolen weapon-grade plutonium and had made contact with residents of the closed city of Sarov, home of one of Russia’s premier nuclear weapons laboratories, to try to arrange a deal.
Bunn, Matthew, and Anthony Wier. "The Seven Myths of Nuclear Terrorism." Weapons of Mass Destruction and Terrorism. Ed. Russell D. Howard and James J.F. Forest. McGraw-Hill, 2007.