US admits it cannot stop North Korea's nuclear programme

America is refocusing its North Korea policies to concentrate on blocking the export of nuclear weapons materials by Pyongyang – a tacit admission that Washington can realistically do little to prevent their manufacture.

The shift in position, which emerged after talks between President George Bush and John Howard, the Australian Prime Minister, in Texas at the weekend, came as the US and the secretive Communist state jockeyed over a deal to shut down the North's clandestine weapons programmes.

Talks last month in Beijing ended inconclusively after Pyongyang demanded massive economic aid and a written security guarantee from Washington in return for scrapping its nuclear activities. Yesterday the North demanded a response to the "bold proposal" it outlined to James Kelly, the chief State Department negotiator to Korea. US officials said Pyongyang told Mr Kelly that it possessed nuclear weapons and threatened to use or export them if Washington did not make concessions.

America now seems to be acknowledging it has no way of establishing the size of any Korean arsenal. The assumption has long been that the North possessed one or two devices, using the plutonium-based technology that was shut down under a 1994 agreement with the Clinton administration. But if Pyongyang's claims are true, that it has already reprocessed enough spent fuel rods to make half a dozen weapons more, the danger would be much greater.

North Korea has long been identified by arms control groups as the world's greatest proliferation threat: indeed North Korean missile technology almost certainly gave Pakistan the delivery system for its nuclear deterrent, which it tested last year.

Those fears resonate even louder here after the trauma of 11 September 2001.

The greatest worry of the Bush administration is not that Pyongyang will start another war on the Korean peninsula, thus entering direct conflict with America, but that it would sell its technology and weapons material to outlaw states or to terrorist groups such as al-Qa'ida, in return for hard currency.

The new line from Washington suggests that the Bush administration is now ready to impose a strict embargo to quarantine the North – or even take military action – if it believes weapons technology is being sold abroad by Kim Jong Il's regime.

¿ A Pakistani Foreign Ministry official said yesterday that the country was ready to eliminate its nuclear weapons, if India did the same. The Kashmir question had to be settled first. Aziz Ahmed Khan said: "If India is ready to de-nuclearise, we would be very happy to de-nuclearise."