US envoy Christopher Hill said Friday that he had held "good discussions" with North Korean officials as he tried to kickstart a six-nation process for ending Pyongyang's nuclear programme.

China's official Xinhua news agency quoted Hill as saying that he had met North Korean Foreign Minister Pak Ui Chun and Deputy Foreign Minister Kim Kye Gwan, Pyongyang's chief negotiator at the six-party talks.

Hill was reportedly en route to Seoul, where he was scheduled to brief South Korean officials and media later Friday, South Korea's Yonhap news agency said.

Hill said Thursday that he hoped to "make up for some time we lost this spring" through his talks this week, referring to the stalling of the six-party process over the transfer of North Korean funds.

His two-day visit was the first by a high-ranking US official to North Korea in five years.

The US assistant secretary of state for East Asian and Pacific affairs is on a tour of countries involved in the nuclear talks involving the two Koreas, the US, China, Japan and Russia.

His trip to Pyongyang came four days after North Korea invited UN nuclear inspectors back into the country to begin the process of shutting down the Yongbyon reactor as required by a Feb 13 six-party agreement.

The closing of Yongbyon has been delayed for more than two months because of a dispute over funds in a North Korean bank account.