The Al Qaeda has more than 18,000 fighters waiting for orders to attack targets in Europe and the United States, preferably with weapons of mass destruction, a leading think-thank said on Tuesday.

Despite the killing or capture of about 2,000 Al-Qaeda fighters, including some key figures, the group remains a powerhouse for terrorists operating in more than 60 countries, the International Institute for Strategic Studies warned.

"Al Qaeda must be expected to keep trying to develop more promising plans for terrorist operations in North America and Europe, potentially involving weapons of mass destruction," IISS director John Chipman said.

"Meanwhile, soft targets encompassing Americans, Europeans and Israelis, and aiding the insurgency in Iraq, will suffice."

The 18,000 figure is based on intelligence estimates. The Al-Qaeda trained at least 20,000 fighters in its camps in

Afghanistan before the US and its allies ousted the Taliban regime. Much damage has been inflicted on political and military affairs across Europe since the Iraq war began in March last year, the IISS said.

The report said: "Politically, it split the US and major continental European powers, leaving the United Kingdom uncomfortably in the middle, and induced uncertainty in other governments about the extent of any contribution to the post-conflict effort."