Al-Qaeda's deputy chief Ayman al-Zawahiri yesterday claimed global warming was helping militant Islamic extremism.

Terror mastermind Osama bin Laden's deputy also launched an astonishing attack on Iran in a two-hour audiotape posted on an Islamic militant website.

He said global warming reflected "how criminal, brutal and greedy the Western Crusader world is, with America at the top".

The Egyptian surgeon accused Shiite Iran of trying to discredit the Sunni al-Qaeda terror network by spreading a conspiracy theory that Israel was behind the September 11 attacks.

Al-Zawahiri said: "Iran's aim is clear - to cover up its involvement with the US in invading Muslim homes in Afghanistan and Iraq."