The International Institute for Strategic Studies (IISS) said the United States, through last year's invasion and the ongoing occupation of Iraq, had shown a desire to change the political status quo in the Arab world to advance its own strategic and political interests.

"Al-Qaeda seeks, among other things to, to purge the Arab and larger Muslim world of US influence," the IISS said, referring to the terror group.

"Accordingly, the Iraq intervention was always likely in the short term to enhance jihadist recruitment and intensify al-Qaeda's motivation to encourage and assist terrorist operations," it added.

As examples of this increased threat, the IISS cited May 2003 attacks in Saudi Arabia and Morocco, the gathering of foreign fighters against the US-led coalition in Iraq, November 2003 attacks in Saudi Arabia and Turkey and the March 2004 train bombings in Madrid.

The assessment was contained in the Institute's annual report for 2004 of the military capabilities and defence economics of 169 countries around the world.