Printer cartridge bomb plot planning revealed
The group thought to be behind the recent attempt to bomb cargo planes has given an explanation of their strategy.
The remarkably detailed account appears in an online magazine produced by the group al-Qaeda in the Arabian Peninsula.
The group said it cost just $4,200 (£2,600) to mail two parcel bombs from Yemen last month.
They said the attempted attack would be the start of a strategy of using smaller, but more frequent operations whose aim was "to bleed the enemy to death".
Unusually for al-Qaeda, they released many details of the planning of the attack, including how long it took and how many people were involved.
They even list the precise costs: two Nokia mobile phones, $150 each, two HP printers, $300 each, plus shipping, transport and other miscellaneous expenses. It could almost be a company report.
More ominously, they warned that they would spread details of their methodology to other al-Qaeda branches around the world.
"We have never seen a militant group in the al-Qaeda orbit ever release - let alone a few weeks after - such a detailed accounting of the philosophy, operational details, intent and next steps following a major attack," said security expert Ben Venzke of the IntelCenter, a group that monitors terrorist threats.
The level of detail suggests a level of confidence - perhaps even rising to boasting - from the group, who clearly feel secure in their hideout in the increasingly lawless country of Yemen.
The comments sound like they could have been written, or at least published, by Anwar al-Awlaki.
He is a Yemeni-American national, now thought to be in hiding in Yemen, who is known for his communication skills. The online magazine Inspire, in which the comments appear, is believed to be his creation.
The new strategy outlined in the magazine may, to some extent, be a case of making virtue of necessity.
For all its recent high profile attempts, al-Qaeda has not managed to mount a major international attack for some time.
So instead, the group is talking of launching a number of smaller attacks which, even if successful, would not result in large numbers of casualties.
The aim would be as much to cause economic disruption as to kill people. The strategy also takes the concept of "terrorism" back to its roots - the aim of causing maximum fear from the minimum of effort.
"It is such a good bargain for us to spread fear amongst the enemy and keep him on his toes in exchange of a few months of work and a few thousand bucks," the group said on the magazine site.
There may also be an element of disinformation, designed to lead Western intelligence agencies astray.
But the top American military officer, Admiral Mike Mullen, told the American network CNN: "This branch of al-Qaeda is very lethal and I believe them - in terms of what they say they're trying to do."