Western powers believe that Iran is running short of the raw material required to manufacture nuclear weapons, triggering an international race to prevent it from importing more, the Times of London reports.

Diplomatic sources believe that Iran’s stockpile of yellow cake uranium, produced from uranium ore, is close to running out and could be exhausted within months. Countries including the United States, Britain, France and Germany have started intensive diplomatic efforts to dissuade major uranium producers from selling to Iran.

Before Christmas, Britain's Foreign and Commonwealth Office sent out a confidential request for its diplomats in Kazakhstan, Uzbekistan and Brazil, all major uranium producers, to lobby governments not to sell uranium products, specifically yellow cake, to Iran.

Iran’s stock of yellow cake, acquired from South Africa in the 1970s under the Shah’s original civil nuclear power program, has almost run out. Iran is developing its own uranium mines, but does not have enough ore to support a sustained nuclear program.

The request, news of which emerged after an international investigation by The Times, was part of a drive by six countries — the U.S., Britain, France, Germany, Australia and Canada — to choke off supplies of uranium to Iran. It is a move that, while unlikely to cripple any effort to develop a bomb, would blunt its ambitions and help to contain the threat, sources told the Times.

The international effort to choke off supplies of yellow cake to Iran reflects mounting concern that 2009 is likely to be a pivotal year for Iran’s nuclear program.

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