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".

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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."