A speaker believed to be the al-Qaida leader in Iraq said in an audiotape found today on a website that one of his top lieutenants was killed in last year’s US-led assault on the insurgent stronghold of Fallujah.

US and Iraqi forces in Fallujah have uncovered the largest-yet weapons cache in the one-time rebel bastion, finding the stockpile inside a mosque led by a key insurgent leader.