WASHINGTON, Feb 2: The United States has developed new evidence which bolsters earlier indications that North Korea is the source of nuclear material exported to Libya, US officials said on Wednesday.

The new data also involves more proof that Pyongyang reprocessed all 8,000 spent fuel rods from a nuclear facility at Yongbyon, enough to fuel about a half dozen nuclear weapons, officials said.

Experts said the new information appeared to confirm what was previously known rather than to break new ground. The United States and other countries have been urging Pyongyang to return to multilateral talks on its nuclear programmes.

North Korea has been watching for President George W. Bush's State of the Union address on Wednesday night for signs of US interest in engaging with the reclusive communist state.

The New York Times reported on Wednesday that nine months ago, international inspectors came up with the first evidence that North Korea might have provided Libya with nearly two tons of uranium hexaflouride, the material that can be fed into nuclear centrifuges and enriched into bomb fuel.

Libya surrendered its huge cask of the highly toxic material to the United States when it dismantled its nuclear programme last year, it said. Now, intelligence officials say, extensive testing conducted at the Oak Ridge National Laboratory in Tennessee over the last several months has concluded that the material did not originate in Pakistan or other suspect countries, and one official said that "with a certainty of 90 percent or better, this stuff's from North Korea," the article said. -Reuters