North Korean leader Kim Jong Un appeared today to claim the country has developed a hydrogen bomb, a step up from the less powerful atomic bomb.

Kim made the comments as he toured the Phyongchon Revolutionary Site, which marks the feats of his father who died in 2011 and his grandfather, state founder and eternal president, Kim Il Sung, the North's state-run television KRT said.

"The work of President (Kim Il Sung) turned the DPRK into a powerful nuclear weapons state ready to detonate a self-reliant A-bomb and H-bomb to reliably defend its sovereignty and the dignity of the nation," KRT news reader quoted Kim Jong Un as saying.

KRT showed still photographs of Kim looking around the site today without specifying the date of visit.

An official at South Korea's intelligence agency told Yonhap news agency that there was no evidence that the North had hydrogen bomb capacity, and believed Kim was speaking rhetorically.

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