Washington, March 13 (Reuters): Information obtained from accused Pakistani nuclear scientist Abdul Qadeer Khan suggests North Korea began to pursue a highly enriched uranium programme for nuclear weapons several years earlier than originally thought, US officials said yesterday.

The officials, interviewed by Reuters, cited this disclosure as evidence that Pakistan has been cooperative in sharing with Washington the secrets of Khan’s global network that sold nuclear technology to Iran, North Korea and Libya.

US allegations about a weapons-grade programme are central to six-party talks on North Korea’s nuclear plans and US officials said they have used Khan’s information to buttress their case with their negotiating partners.

But officials also said that five weeks after Khan confessed his deeds, the US still has not had direct access to the disgraced scientist. Khan presumably could provide concrete answers to many key questions including whether he sold nuclear weapon designs to Iran.

Some sources said the US was unhappy with Pakistan’s cooperation but a senior official said these reports are “highly exaggerated.”