London - Documents with detailed designs for missiles, bombs and nuclear weapons were found in Kabul safe houses used by Osama bin Laden's al-Qaeda network, it was reported last night.
The partly-burnt papers were found by the Times newspaper in a hastily abandoned house in the Karta Parwan quarter of the city, the newspaper reported.
There are descriptions of how the detonation of TNT compresses plutonium into a critical mass, sparking a chain reaction, and ultimately a thermonuclear reaction, it said.
Documents were found in two of four al-Qaeda houses which had been used by Arabs and Pakistanis and even reportedly by bin Laden himself, the newspaper said.
The discovery of the detailed instructions, written in Arabic, German, Urdu and English, confirms the West's worst fears of an attack far worse than the September 11th atrocities, the newspaper noted.
Nuclear experts say the design suggests bin Laden may be working on a fission device similar to Fat Man, the bomb dropped on Nagasaki, but they emphasise it is extremely difficult to build a viable warhead, it added.