United Nations inspectors have found a new type of centrifuge design in Iran and other experiments that Tehran has failed to declare, despite its claim in November that it had fully disclosed its nuclear programme.

The new findings come at a time of heightened concern about nuclear proliferation after the discovery of the rogue procurement network headed by Abdul Qadeer Khan, the so-called father of Pakistan's nuclear bomb...

...The new information comes as the UK, France and Germany continue to press Iran to suspend uranium-enrichment activities. This was part of an agreement reached in Tehran last October, but the parties have since disagreed on the interpretation of the suspension clause.

To the frustration of the Europeans, Tehran is believed to have continued to assemble centrifuges, which European governments consider a failure to fulfil obligations under the agreement.

"We're going to have quite a difficult period between now and the next [IAEA] board meeting," said a western official on Wednesday...

The United States is considering action over what it says is Iran's continued pursuit of nuclear weapons, a senior administration official has said. John Bolton's comments came amid reports that UN inspectors had found undeclared nuclear technology in Iran.

Inspectors reportedly found designs for a uranium centrifuge, which is capable of producing weapons-grade material.

The Islamic republic has again denied that its nuclear programme is being used for military purposes...