SEOUL: US and Republic of Korea (ROK) authorities have found no concrete evidence yet that the Democratic People's Republic of Korea (DPRK) is reprocessing spent nuclear fuel rods to harvest weapons-grade plutonium, a news report said yesterday.

The DPRK said last month that it had begun the reprocessing work at its Yongbyon nuclear complex - one of a series of steps the nation has taken in protest over international criticism of its April 5 rocket launch.

Pyongyang has also quit international nuclear talks, kicked out all international nuclear monitors and threatened to conduct its second nuclear atomic blast and a long-range missile test.