The Yemen-based branch of Al-Qaeda has vowed further small but frequent attacks against the West such as last month's cargo plane parcel bombs, in a "strategy of a thousand cuts" that will "bleed the enemy to death", a monitoring group said.

Al-Qaeda in the Arabian Peninsula (AQAP) said the packages it put aboard freight planes bound for the US in late October were never intended to cause mass casualties, but were aimed at creating maximum economic damage.

The group said the parcels, which were intercepted in Dubai and Britain, were part of "Operation Hemorrhage," a plan that had cost just 4,200 dollars to mount.

It said there was now little focus on large-scale mass-casualty attacks like those on New York and Washington in September 2001.

"To bring down America we do not need to strike big," the network said in an English-language magazine called Inspire, which was monitored Saturday by the US-based Intelcenter.

"In such an environment of security phobia that is sweeping America, it is more feasible to stage smaller attacks that involve less players and less time to launch and thus we may circumvent the security barriers America worked so hard to erect," AQAP said.

"This strategy of attacking the enemy with smaller, but more frequent operations is what some may refer to as the strategy of a thousand cuts. The aim is to bleed the enemy to death."

The two parcels were addressed to synagogues in Chicago and found to contain the hard-to-detect explosive PETN hidden in ink toner cartridges.

A massive global security clampdown on airfreight followed the discovery, with a number of countries banning cargo or flights originating from Yemen, including the United States, Canada and several western European countries.

The AQAP magazine details the "total bill of 4,200" dollars for Operation Hemorrhage, adding that it was three months in the planning and execution.

"On the other hand this... will without a doubt cost America and other Western countries billions of dollars in new security measures. This is what we call leverage.

"From the start our objective was economic... It was determined that the success of the operation was to be based on two factors: The first is that the packages pass through the latest security equipment.

"The second, the spread of fear that would cause the West to invest billions of dollars in new security procedures.

"We will continue with similar operations and we do not mind at all in this stage if they are intercepted. 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 magazine says AQAP intends to pass on its know-how to other radical Islamists around the world, to encourage them to mount similar operations.

"We are laying out for our enemies our plan in advance because... our objective is not maximum kill but to cause a hemorrhage in the aviation industry, an industry that is so vital for trade and transportation between the US and Europe."

IntelCenter chief executive Ben Venzke said the level of operational detail AQAP had provided in the magazine marked a departure for Islamists.

"We have never seen a jihadist group in the Al-Qaeda orbit ever release, let alone only a few weeks after, such a detailed accounting of the philosophy, operational details, intent and next steps following a major attack," he said.

"This may represent a new level of interaction by jihadi groups following an operation and is a far cry from the days of shadowy claims and questions as to who was actually responsible.

"AQAP is a dedicated, unwavering and sophisticated group. It will continue to strike at the US in creative new ways and it is only a matter of time until one of their attacks results in thousands dead and/or severe economic damage."