Article published on the 2008-10-03 Latest update 2008-10-03 10:35 TU
Hill had extended his trip to Pyongyang by one day and crossed back into South Korea early on Friday.
There was no immediate information as to whether the trip had been successful in brokering a compromise agreement between North Korea and the US on Pyongyang's nuclear tests. Hill is to meet his counterparts from Japan and South Korea on Friday to brief them on the results.
The US State Department said it had spoken to Hill on Thursday but said that he had not yet given a full report. He is to travel on to Beijing for talks with China.
North Korea closed a nuclear complex in July 2007 and began it dismantle it four months later. It also delivered a report of nuclear activities to China.
It now says that says it will soon begin work to restart a plutonium reprocessing plant, which could produce more bomb-making material from spent fuel rods, unless Washington removes it from a blacklist of states alleged to support terrorism.
The US is demanding inspections before dropping North Korea from the list.