The self-proclaimed mastermind of the 9/11 terror plot told interrogators at Guantanamo Bay that Al Qaeda has a nuclear bomb somewhere in Europe and would detonate it if Usama bin Laden was ever captured or killed, The Daily Telegraph reported, citing WikiLeaks’ cables.

Khalid Sheikh Mohamed, one of the top prisoners at the facility, called the plan a “nuclear hellstorm.” The report, which was first published late last month, said some detainees had comprehensive knowledge of Western countries’ nuclear defense.

There was no immediate indication that bin Laden's killing last weekend by the U.S. would prompt Al Qaeda to carry out such a threat, or if it even has the capabilities. To be sure, cables show U.S. authorities uncovered a number of attempts by Al Qaeda to obtain nuclear materials, according to the report.

The WikiLeaks cables about Guantanamo, obtained and detailed last month by several news organizations, illustrated how intelligence agencies employ information obtained by the 780 prisoners. Although some of the information is proved to be erroneous, still some appears to be actionable.

Separately, a prisoner described as the 20th 9/11 hijacker said the terror group is seeking to recruit staff at Heathrow Airport in London and plotted major chemical and biological attacks against the U.S.