WASHINGTON: The core of al Qaeda has been severely weakened and likely is unable to launch “large-scale” attacks on Western targets, the US national intelligence director said on Tuesday.

Al Qaeda has suffered steady losses among its senior ranks since 2008, diminishing the network's central leadership “to a point that the group is probably unable to carry out complex, large-scale attacks in the West,” James Clapper said in an annual assessment presented to lawmakers.

But the group has not abandoned its declaration of war against the United States, and its affiliates, particularly in Yemen, are plotting to attack America and its allies, Clapper told the Senate Intelligence Committee.

Extremists linked to or sympathetic with al Qaeda also are seeking to exploit turmoil in the Middle East, including Syria's civil war, according to his report.