Al-Qaida remains a "potent" international terrorist network with more than 18,000 trained members at large in up to 90 countries, and could take a generation to dismantle, a leading international affairs thinktank warned yesterday.
The warning came in the annual strategic survey of the International Institute for Strategic Studies whose author, Jonathan Stevenson, said the Riyadh bombings "bore the hallmarks" of an al-Qaida operation.
The bombings "may be the first indication that the regime change in Iraq in the short term is going to cause a terrorist backlash and be an inspiration for terrorists", he added.
Although the audacity and sheer power of the American-led invasion could have a "suppressive effect" on terrorists, it was equally likely that the conflict "increased al-Qaida's recruiting power", he said.
The report warns that al-Qaida has reconstituted itself since the war in Afghanistan and was now "doing business in a somewhat different manner, but more insidious and just as dangerous as in its pre-September 11 incarnation".
It describes al-Qaida as a "potent transnational terrorist organisation that could take a generation to dismantle". With improved European and American defences, al-Qaida could "content itself with softer high-value targets".
The report says that the US and its allies have had some successes against al-Qaida, with about 2,700 known or suspected terrorists arrested, including its operations chief, Abu Zubaydah and Khalid Sheikh Mohammed, the third in command.
They have captured or killed 10 "senior leaders" as well as some 2,000 rank and file members, the institute says. That left a "rump" leadership of around 20 and some 18,000 jihadists who had been through al-Qaida training camps in Afghanistan.
It said that changes in the organisation since the Afghan conflict could make it more difficult to combat: "The counter-terrorism effort also, perversely, impelled an already decentralised and elusive transnational network to become even harder to identify and neutralise."
The report adds: "Thanks to technology and the multinational allure of jihadism, the Afghanistan camps were [now] unnecessary."
While its leaders had "blended" into Pakistani cities such as Karachi, new technology enabled it to operate as a "virtual entity", without the need for physical bases.
"The only physical infrastructure al-Qaida required were safe houses to assemble bombs and weapons caches," the report says.
"Otherwise, notebook computers, encryption, the internet, multiple passports and the ease of global transportation enabled al-Qaida to function as a 'virtual' entity that leveraged local assets - hence local knowledge - to full advantage in coordinating attacks in many 'fields of jihad'."
The report says that al-Qaida is now thought to have mid-level coordinators in dozens of countries who had been trained in Afghanistan, providing their local followers with logistical and financial aid.
It meant that the al-Qaida leadership could leave actual terrorist attacks - the "heavy operational lifting" - to "local foot-soldiers", as happened in last year's bombings in Bali and Kenya. The "multinational allure of jihadism" meant that any who were lost could easily be replaced.
"If the minions were killed or caught, their spectacular demise in the name of Islam and al-Qaida's audacious operational reach" would move others to take their place, the report said. "The process was, in theory, self-perpetuating."
Despite freezing £78m of suspected terrorist assets, al-Qaida can still draw on "a stream of essentially unregulated cash" from donations from Muslim sympathisers around the world.