A series of video tapes found in an Afghan house used by Osama bin Laden illustrate the extent to which he was training terrorists and the lengths to which he was prepared to go to kill his enemies.
Footage obtained by a journalist working for CNN, the US cable news network, shows dogs being exposed to poisonous gas, possibly home-made nerve gas. All died.
The archive of 64 videotapes, which spans more than a decade and was part of a larger cache of 200 tapes, also shows previously unseen images of bin Laden and his top aides, including the Saudi exile's personal security arrangements and training procedures for terrorists. One scene shows bin Laden with his security detail, firing shots in the air as they prepare to announce their new jihad, or holy war, against Americans in 1998.
CNN began broadcasting the tapes yesterday, including the one which shows three dogs dying. "I think what we have here is a very crude binary weapon," said Mr Jonathan Tucker, an arms expert on the programme.
Bin Laden and his al-Qaeda organisation are believed widely to have been behind the September 11th attacks on the US last year in which more than 3,000 people died. Virtually all the tapes pre-date September 11th, although one features segments from televised news reports of the attacks, according to CNN.
The network said it had shown the tapes to several experts who said the footage depicted al-Qaeda operatives training, practising urban combat, assassinations and kidnappings. Video training for terrorists included a three-hour's of instructions on how to make purified TNT explosive from easy-to-get materials.
CNN's journalist in Afghanistan, Nic Robertson said an Afghan source passed him the tapes in a remote region.