The National Intelligence Service says it believes North Korea has been trying to develop highly enriched uranium but is not likely to have yet produced the material nor have it in its possession.

In a report to the National Assembly's information committee, a senior intelligence official said that Pyongyang had obtained some of the equipment for uranium enrichment since 2000. But the official said Pyongyang has not been able to construct an enrichment factory, as further import of necessary equipment was cut off due to strengthened international monitoring.

The official said the North may have already produced one or two conventional nuclear weapons from the 10 to 14 kilograms of plutonium it acquired before the IAEA inspections began.

However, he was quick to add that the communist state is presumed to have not yet attained the technology to manufacture smaller and lighter nuclear weapons, which could be loaded onto missiles.