The Bush administration is planning to use nuclear weapons against Iran, to prevent it acquiring its own atomic warheads, claims an investigative writer with high-level Pentagon and intelligence contacts.

President George W Bush is said to be so alarmed by the threat of Iran's hard-line leader, Mahmoud Ahmedinejad, that privately he refers to him as "the new Hitler", says Seymour Hersh, who broke the story of the Abu Ghraib Iraqi prisoner abuse scandal.

Some US military chiefs have unsuccessfully urged the White House to drop the nuclear option from its war plans, Hersh writes in The New Yorker magazine. The conviction that Mr Ahmedinejad would attack Israel or US forces in the Middle East, if Iran obtains atomic weapons, is what drives American planning for the destruction of Teheran's nuclear programme.