BEIJING - NORTH Korea says it has 'weaponised' enough plutonium for four to five nuclear weapons, a United States expert said yesterday after talks in Pyongyang

North Korea has made a series of demands as well as offers of cooperation over its nuclear programme as US President-elect Barack Obama prepares to enter the White House.

The North's leader Kim Jong Il appears to have given up handling many day-to-day tasks after suffering a stroke and this may explain the North's hardening stance, said Mr Selig Harrison, a scholar at the Woodrow Wilson International Centre for Scholars, a policy institute in Washington.

Still, the officials repeatedly stressed that the North wants better relations with the incoming Obama government and hopes Mr Obama will 'initiate new moves towards normalised relations,' Mr Harrison said.

He said senior North Korean officials had told him this week that 30.8kg of plutonium their government had listed as part of a preliminary disarmament agreement had been 'weaponised'.

He said when he asked what 'weaponised' meant, 'the answer I got was 'It means warheads''.

'That means North Korea has four or five nuclear weapons, depending on the grade of plutonium, the specific weapons design and desired explosive yield.'

He said all the four senior Pyongyang officials he met, including Mr Ri Gun, the Foreign Ministry official in charge of dealings with Washington, said plutonium was now out of bounds of inspections intended to advance the now-stalled six-party disarmament talks.

Mr Harrison was speaking to reporters in Beijing after returning from five days in Pyongyang, his eleventh visit to the isolated North since 1972.

The North Korean claims could not be verified, Mr Harrison said, but they underscored a hardening of the state's position even as it made offers of cooperation to Mr Obama.

The Pyongyang officials were vague about what weaponisation meant, but it appeared most likely the plutonium would be fitted in missile warheads, Mr Harrison said.

North Korea has delayed implementing a nuclear disarmament agreement struck at the six-party talks in Beijing, unwilling to accept verification rules demanded by the other countries in the talks and saying they have not abided by their energy aid vows.

'The prospects for the six-party talks, on the basis of my assessment, are very gloomy,' said Mr Harrison. The talks bring together North and South Korea, China, the US, Japan and Russia.

Mr Harrison said North Korea wanted construction of two unfinished light-water nuclear energy reactors in return for dismantling its Yongbyon nuclear plant.

It also says verification of its nuclear activities hinges on the United States and South Korea agreeing to open any nuclear weapons activities in the South to similar probing.

Mr Harrison said the North's Mr Ri Gun told him: 'We are not in a position to say when we will abandon nuclear weapons. That depends on when we believe there is no US nuclear threat.'

North Korea's state media also said earlier yesterday that Pyongyang would not give up its nuclear ambitions as long as a US nuclear threat persisted.

North Korea's army said yesterday it would assume an 'all-out confrontational posture' against the South and wipe out the conservative government in Seoul for refusing to cooperate. South Korea's military ordered a border alert yesterday following the threat.

Analysts said the North, which in 2007 signed an aid-for-disarmament deal with the US and four regional powers, is trying to ensure it remains a priority for Mr Obama despite his other daunting economic and foreign policy challenges.

Reuters, AFP, AP