A spokesperson for the U.S. Bureau of Prisons tells ABC News that federal facilities on American soil currently house:
240 inmates "with a nexus to or history of international terrorism";
119 inmates "with a nexus to or history of domestic terrorism."
The most serious incident involving any of them, the spokesperson said, was when on November 1, 2000, Mamdouh Mahmud Salim, a former top aide of Osama Bin Laden, stabbed federal prison guard Louis Pepe at the Metropolitan Correctional Center, causing him severe brain damage.
Salim is an inmate of the ADX Florence "Supermax" facility in Florence, Colorado, which is also home to Jose Padilla, Mahmud Abouhalima, Ramzi Yousef, Eric Rudolph, Terry Nichols, Zacarias Moussaoui, Wadih el-Hage and Richard Reid.