Palo Alto (US): Four years after Pakistan s top nuclear scientist confessed to leaking weapons technology to North Korea, the North Koreans have denied receiving any such help, an American researcher said.

The North Koreans dismissed the confessions from Pakistan, saying, "That s your story," researcher Siegfried Hecker said.

The North Koreans also told Hecker they had nothing to do with a suspected Syrian nuclear site destroyed by Israeli fighters in September, he said. News media reports, some quoting unidentified US officials, have said the strike hit a nuclear installation linked to North Korea.

Hecker, a Stanford University professor and a former director of the Los Alamos National Laboratory, said he questioned North Korean officials on the two issues during a trip to that country from February 12-16. Hecker also visited the country s Yongbyon nuclear facility on February 14.

Pyongyang s past actions are sticking points in disarmament efforts under way now, because under recent agreements, North Korea is supposed to provide a full accounting - a declaration - of its nuclear programmes and activities.

Hecker has visited the North annually for the past five years, and last week s trip was unofficial. Nevertheless, he pressed North Korean officials, whom he would not identify, on issues of concern to the United States, he said.

He told a small group of reporters on Wednesday that he had made plain that the issue of the Syrian site destroyed in September was "high on the list of American concerns." And US officials are still awaiting North Korea s account of nuclear ties to Pakistan following Islamabad s acknowledgments years ago of the transfers, he said.

Source : PTI