Mr Hill, who is also US Assistant Secretary of State, said the DPRK’s denuclearisation process is at an important stage, world media reported.

He will visit the Yongbyon nuclear complex to monitor disablement work being carried out as part of a six-way denuclearisation deal.

He will also meet with the DPRK’s Deputy Foreign Minister Kim Kye Gwan and other high-ranking military officials, as well as his Korean counterpart.

The disablement of three nuclear facilities in Yongbyon began in early November as part of the second phase of the DPRK’s denuclearisation.

The DPRK has promised to disable its nuclear facilities and to submit a complete declaration of its nuclear programmes by the end of the year.

Meanwhile, Iran appears “less determined” to develop nuclear weapons than previously thought, US intelligence officials said.

Tehran halted its nuclear weapons program in 2003 but is continuing to enrich uranium, a National Intelligence Estimate assessment has concluded.

Enriched uranium is used in nuclear bombs but Tehran says the aims of its nuclear activities are peaceful. Iran is currently under sanctions from both the UN Security Council and the US.